1. What happened
When upgrading to 2019.4.29 customer has discovered Animation Controllers are not displaying the Inspectors for nodes.
2. How we can reproduce it using the example you attached
a )Project attached is for 109.4.29
b) Open it
c) Look in the Animator window
d) Click on any of the nodes such as "Door_Open" in the "Rocket_Door" layer
e) Not that the Inspector is not showing anything for these nodes
f) Clean out the Library, and re-open in a previous version of Unity ( customer was using 2019.4.21 but 22 thru 28 also seem fine )
g) See that now the nodes above that failed Inspection work fine
Customer says operation is not affeccted, only the Editing.
Possible regression in Animator UI in 2019.4.29