The Bug:

As of 1.19.4 Pre-1, certain mobs no longer panic while taking campfire damage, making many of them just sit there taking damage until they die when they did not before in just one snapshot earlier, 23w07a. 

I suspect it may have something to do with bug fixes like MC-253211, but this affects mobs that weren't involved with these fixes, such as Allays. 

Here is a video of a group of mobs (Frog, Allay, Sniffer) in 23w07a, panicking as expected:
23w07a_Campfire.mp4

Here is another with the same group in 1.19.4 Pre-1, and the same is true for versions onward:
1194Pre1_Campfire.mp4

Steps to Reproduce:

1. Open 23w07a and place some campfires. Spawn some mobs, such as frogs or allays on the campfire
2. Notice how they will panic from taking damage, allowing them to move off the damage source
3. Do the same in 1.19.4 Pre-1 and onward; see how the mobs now no longer take damage

I'm not sure of the complete list of mobs that are affected or if its just campfires/magma. Further information will be provided if needed.