I've had this issue for a couple of months now. I shoot pictures on my Canon 6D MK II and use the .CR2 (RAW) format to edit them in Lightroom Mobile. I started using this method in January 2021 and it was all going fine until June 2022, when my RAW-files suddenly began to appear much darker than how they were displayed on the camera monitor, my pc, and my mobile phone's gallery. I have no selected presets for the import and I don't know what my camera could have to do with all that as I have changed no settings for at least a year. Meanwhile, JPG-files remain unchanged and the support didn't really help me.
I added an example. Thanks in advance and have a nice day, Moritz.