Canon removes EOS R5c firmware 22.214.171.124 from support sites across the globe. Vitali Beliak reports that there is there is “a bug in new R5C firmware 126.96.36.199 for photography shooters.
If you are shooting in one of the three custome modes, C1 C2 C3 custom modes, the R5c delivers R5 pixel shift feature resulting in huge file sizes.
“Just switch it into one of custom modes. Turn off camera, then turn it back on. The pixel shift should be on at this point. I tried resetting settings, but it didn't help.” –
Despite having had several months to develop and test, the firmware update proved too big of an update to allow Canon to properly test the outcomes. Perhaps this will encourage Canon to issue smaller firmware updates in the future but more frequently. Small updates take less time to design, develop and test.