EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

[fstopPhoto]

I started using this camera last September (2024) and every single time I use it the ISO randomly changes on its own.  I typically shoot all indoor, low light situations with ISO 3200 - 4000.  Exposures will be fine the suddenly either dark or overexposed.  The ISO might go down to 400 or 640 or up to 12,500 for no reason whatsoever.  This happens multiple times a day, every single day I use it.  I'm ready to throw it out. 

I have turned the return to auto ISO off and this does absolutely nothing.  It's driving me crazy!  Nothing works to change this.  I have set the ISO range to a low of 3200 and a high of 6400, which I don't want it to be that high but that's the only option, set the ISO to 3200 and it will still change ISO to AUTO or to any ISO between 3200 and 6400 for no reason.  

I thought maybe my forearm is touching the screen and somehow changing the ISO, which is hard to believe, so I turn the camera off when walking.  I can turn it back on and the ISO has changed from my original settings.  I can shoot a series of photos and it changes ISO on the next photo.  

I have reset the camera to factory settings.  The firmware is up to date but I downloaded it again and reinstalled the most current firmware and it still does it.

This is absolutely insane and I can't figure out why it's happening or how to get it to stop. 

Every once in a while the white balance will also change randomly but that has only happened a few times in the last 7 months of use, whereas the ISO changes every single day, multiple times a day.  

Any suggestions or Canon employees who can help with this?

Thanks,

Dave  

[fstopPhoto]

Thanks, but my camera is already set that way and it still happens.  It's been set that way since the first time it happened and I looked it up and found that as a solution.  Since then it has continued to do it even though it should not.  

[fstopPhoto]

I set my ISO at 3200 or 4000 to start.  My ISO range in 3200 to 6400 so if it changes it's at most a 1 stop change.  I set my Auto range to the same and my ISO speed range for the same reason.  So other than the Auto range in your image it's the same thing.  

[fstopPhoto]

Here's a Dropbox link to the RAW files and XMP files.

https://www.dropbox.com/scl/fo/cro8noej76jv8b2201pjv/AGmNuo3VTk-0kzB61CBCfpk?rlkey=39f126710quupzyp4...

[hclark1027]

I did a wedding last night.  I came home and the majority of the larger group photos were SO GRAINY I was taken aback.  I use a Canon R6 Mark II and have never had this problem but with the wedding I rented a second once to be able to take pics with different lenses.  And guess what this happened a ton.  But what I am so pissed at is it went to the highest setting and I guess never switched back despite me putting it back to 2500.  After it automatically switched on its own I thought it was weird but just thought I did something.  Even though I have been using this camera for a year and a half and my own has never done it.  The rented one did.  I am devastated and don't know how to fix the grain. ITS SO BAD.  If anyone knows any editing software that does it better then Lightroom please let me know! I have to tell my bride and groom this week that the majority of their group photos are grained out so bad I can't even fix them. 

[pcs1]

I'm late to this 'party' but I've observed two possible problems(if I've missed earlier mentions I apologise).

First, have you safety shift on?

Second thing, I downloaded one of the photos and exif says flash was on. Direct after flash has gone off, while it is charging the ISO goes up, when charged it goes down(with mine at least when on auto ISO)