"OPENGL ERROR" on event creation

1. What happened
Getting an error every time I create an event in the Animation Window...
"OPENGL ERROR: The OpenGL context has been modified outside of ApiGLES. States tracking is lost."

2. How we can reproduce it using the example you attached
create a Cube
Open the Animation Window
With Cube selected, click the Create button in the Animation Window to create an empty clip.
Now click the "Add Event" button (line with + icon)... error

This is a 5.2.2p3 regression.