Short description of error
Just noticed in preparing an example file for another bug report (T63304), upon deleting many objects at once (maybe a binded camera or 2 by mistake) the viewport now ignores all camera binds in the timeline and it just uses the last active camera.
All subsequent camera binds don't work either.
Rendering produces the same result as in viewport.
I ran into the issue 3 times before I successfully managed to reduce my file without destroying the camera binds in the animation.
Steps to reproduce
Notice how Camera.023 is the only camera used in the viewport, despite all the many camera binds in the timeline.