I installed 1.3.0 on my R5 on 31 March and was pleased with the apparent improvements in autofocus, with the add-on benefit of manual focus in AF Servo mode. I later installed 1.3.1 on 15 April, and yesterday evening/this morning finally got time to do some test shooting the in back yard (through picture window) on my forest full of bird feeders. It would appear that 1.3.1 has made the single point AF (or spot, expanded, etc.) programmed to my AF-ON button almost useless. Since adding 1.3.1, it now is averaging 6 to 8 presses before it actually achieves focus, and a subsequent press while trying to stay on a moving (hopping) bird blows focus completely out again. Dramatically worse behavior that I saw with 1.3.0. Eye AF still works when it wants to (no better, and no worse than in 1.3.0). This is NOT an improvement. All testing done with RF 100-500 with firmware updated to 1.0.9 at same time camera went to 1.3.0.
That did it - the 100-400 IS II + 1.4 is back on the tripod, this time with a 5D Mk4 instead of the more reliable 7D Mk II, which is almost painful to look through after several months of the R5 EVF. Spring migration has begun here, and I will probably have to revert the R5 to 1.3.0 and then reset the whole camera and redo all the settings, and I no longer have the time to waste on it with warblers on the way up from Galveston. This is a huge disappointment.