Agree that this is most likely laser damage to the sensor.
If this is a mirrorless, realize that a weakness of the mirrorless design (or shooting a traditional DSLR in Liveview mode) leaves the sensor constantly exposed and subject to damage. You have to use the same precautions with these that you would while shooting with a camcorder which also has its sensor constantly exposed.
07/31/2023: New firmware updates are available.
05/31/2023: New firmware updates are available.
05/18/2023: New firmware updates are available.
04/20/2023: New firmware version 1.4.1 is available for EOS R3
03/30/2023: New firmware updates are available.
2/07/2023: New product announcements!EOS R8 EOS R50RF-S55-210mm F5-7.1 IS STMRF24-50mm F4.5-6.3 IS STMRF15-30mm F4.5-6.3 IS STM