[Bug] in Canon R6 Mark II: AF Lock Issue with AF-ON Button Customization (Needs Firmware Fix!

[masilsnap]

I’ve been experiencing a very strange and frustrating AF lock issue on the Canon EOS R6 Mark II. This specific behavior is causing me to miss critical shutter moments during my shoots.

Summary of the Problem:

Settings: I have "Servo AF" assigned to the AF-ON button through the customization menu.

The Issue: After shooting a burst using the AF-ON button, the AF stays locked as if the shutter button is still being held halfway down, even after I completely release all buttons.

The Frustration: While this is happening, the multi-controller (joystick) becomes completely unresponsive, making it impossible to move the AF point to follow the action.

The Anomaly: Unlike the normal behavior of the touch shutter, the AF point stays green and refuses to return to its idle state (white) even after the subject is gone.

Note: The issue disappears immediately if I press the shutter button halfway, but in a live performance shooting environment, that tiny fraction of a second is enough to miss a decisive moment.

I'm sharing this video in hopes that it reaches Canon for a much-needed firmware fix. Has anyone else encountered this "sticky" AF behavior?

EOS R6 Mark II 

[xzebra]

You are more than welcome my friend and sorry this did not resolve the issue.

I know how frustrating it can be and wish you the very best.  

If you don't mind, letting me know what you determine. 

[xzebra]

Stephen - Please note my messages above is not a demeanor to you or any of the other techs.  I understand they all work hard and try to assist.

Simply a frustration by myself after spending thousands with Canon.   While I understand you might not know all the issues/bugs, it is frustrating as a consumer that Canon wanted me to send in my camera @ $250 minimum to diagnose the issue which I found resolution online.

I honestly don’t believe this is the correct thread for a debate, nor should be a debate.  

This post should be about the OP needing assistance and resolution as I did.

Please elevate the OP’s issue to help him resolve.

Thank you!

[Waddizzle]

“ My case seems to be a bit different because it isn't a permanent setting error—it only happens temporarily right after a high-speed burst while using the Servo AF-ON button. The joystick only freezes during that specific "Green AF point" lock-up period. “

 What is the memory card LED doing when this happens?  This brief description sounds consistent with the internal buffer being filled, whic does cause the camera to seemingly stop working.  When the buffer fills, everything stops until all data is written to the card.

Speaking of memory cards, what type do you use? Brand? V90?

[masilsnap]

After more precise testing, I've discovered that this freeze occurs specifically when the Shutter button and the AF-ON button are released simultaneously. > It happens in both High-speed Burst and Single Shooting mode, which confirms it's not a buffer-related issue. I have already tested this with several V60 cards from Transcend, Sony, and Lexar, and the result is consistently the same.

It seems like the camera’s AF algorithm runs into a conflict when processing the simultaneous "release" signals from both buttons, causing the AF point to stay locked (green) and the joystick to freeze. This is a clear software logic error that needs a firmware fix.

[masilsnap]

Thank you for the advice.

I have already contacted official Canon support in Korea and sent my camera in for a professional inspection. The technicians there confirmed that the issue is reproducible not only on my unit but also on their own test units.

They concluded it is not a hardware failure or a configuration error, but a systemic behavior (bug) of the R6 Mark II model. I am sharing this here and on Reddit to raise awareness and collect more data from global users, as individual service center visits cannot solve a firmware-level issue.

My goal is to get this reported to the actual firmware development team, and having other users confirm the same behavior is the most effective way to show that this is a widespread flaw.

[masilsnap]

I am well aware of how One-Shot AF works. However, this is not a normal focus lock.

The issue is that the focus stays locked and the multi-controller (joystick) becomes completely unresponsive even when no buttons—neither the shutter nor the AF-ON—are being pressed.

To confirm this, I sent my camera to an official Canon service center in Korea. The technicians there successfully reproduced the issue on another display unit as well and confirmed it is a bug. However, even the technicians could not identify the specific algorithm causing this conflict, which is why it remains uncertain if or when a firmware fix will be released.

I am sharing this to gather more evidence from the global community to help Canon prioritize this complex software issue.

[masilsnap]

I am the author of this post. Thank you for your active participation in this thread.

I would appreciate it if we could focus on the specific issue I have reported here. To provide further context, my camera has already been inspected by an official Canon Service Center in Korea. The technicians there were able to successfully reproduce the exact same freeze on another display unit at the center.

This behavior consistently occurs when the Shutter and AF-ON buttons are released simultaneously, regardless of the shooting mode (Single or Burst) or the brand of V60 memory card used.

It points toward a firmware-level logic conflict rather than a mechanical issue. I kindly request that you escalate these specific findings to the firmware development team so they can investigate a permanent solution.

[Waddizzle]

“ It happens in both High-speed Burst and Single Shooting mode, which confirms it's not a buffer-related issue. I have already tested this with several V60 cards from Transcend, Sony, and Lexar, and the result is consistently the same. “

A V60 card is too slow for bursts. Do the math for how much data needs to be written per second.  Around 250-300 MB/sec

What shutter mode and burst FPS are you using?

How many images are you capturing in a burst?

Does the memory card LED turn on and stay on when it malfunctions?

Again, everything you are describing is consistent with a buffer overflow.

[masilsnap]

​Actually, this freeze occurs even after taking just 3 frames in Single Shooting mode. This clearly proves that it is not a buffer-related issue.

​Based on my testing, the trigger is not the burst speed itself, but rather when the Shutter button and the AF-ON button are released simultaneously. This is a specific logic conflict that causes the AF system and the UI to lock up.