As promised by Canon, FW 1.5.0 is now released (at least on the UK support site) for the R5.
Quite a list of new features there; the big ones seem to be around improved subject tracking. I'll be installing this soon. There's a corresponding manual update too (according to the update page; I haven't actually found it yet).
It's on the Canon USA support site now.
Firmware Version 1.5.0 incorporates the following enhancements and fixes: 1. Improves head detection performance to support helmets or goggles in winter sports. 2. Adds [Vehicles] selection to [Subject to detect] selection in the [AF] tab to support the detection
of automobiles and motorcycles in motorsports. Adds [Spot detection] when [Vehicles] is selected as the
helmet of the driver or rider*. *Detection may not be possible for ordinary passenger cars or bicycles, or for motorcyclists performing
stunts or kicking up dirt and dust. 3. Improves detection performance for eye detection when: -there are shadows on the face. -hair is hanging over the eyes. 4. Adds support for torso detection of a person. If the eyes, face or head are hidden or cannot be
detected, a person's torso will be detected and tracked continuously. 5. Adds the ability to import manual white balance (MWB) data from the Quick Control screen when
capturing still images. 6. Eliminates the center press operation of the multi-controller to prevent accidentally transferring
images during FTP transfer. 7. Adds the ability, when using EOS Utility for remote shooting with two cards inserted, to set the
recording method and to select which card to be recorded to. 8. Adds [Suppress lower frame rate] to [Smooth] in [Disp. performance], enabling the shooting screen
to be displayed with less drop frame rate even in dark locations. 9. Adds support for the RF 5.2mm F2.8 L Dual Fisheye lens. 10. Changes the default value of [FTP server] → [Passive mode] to [Enable]. 11. Improves operation stability during FTP transfer. 12. Optimizes controls of In-Body Image Stabilization (IBIS) when using specific EF lenses not
equipped with the image stabilization function. 13. Fixes an issue, in which noise occurs along the edges of bright subjects when using Canon Log
for movie recording. Firmware Version 1.5.0 is for cameras with firmware up to Version 1.4.0. If the camera's firmware
is already Version 1.5.0, it is not necessary to update the firmware. Notes: The User Manual on our website has been updated accordingly. Please download the User Manual as well
as the latest firmware. You can download it from the official website. The Applications have been updated accordingly. Please download the Applications as well as the latest firmware.
For anyone in the UK looking for the updated manual -- as far as I can see, it isn't on the UK support page yet. You can however get it from the USA support site: https://www.usa.canon.com/internet/portal/us/home/support/details/cameras/eos-dslr-and-mirrorless-ca...
I installed the firmward updates yesterday for my R5 and R6 units without any issues, and so far it seems to be stable. I am not a videographer, so I have not explored any of those features.
If you are asking if there are others with this issue: speaking for myself, I have had no issues.
To try to assist can you confirm a few things:
1. Has the camera exhibited any issues previous to the upgrade?
2. During the upgrade, where there any issues of any kind?
3. Your battery is an original branded Canon LP-E6NH?
4. Your SD card is not a micro SD card with an adapter?
5. Have you tried doing a factory reset of the camera's configuration?