Fairly frequently, but not 100% of the time, when a waveform is moved to another viewport a waveform in the original viewport (not the one being moved) stops displaying correctly and the console is spammed with OpenGL error 502 (GL_INVALID_OPERATION).

No steps to trigger the issue reliably on cue are known, however if you keep moving waveforms between views it will eventually show up. All recently observed incidents corrupted the bottom waveform in the original viewport, however it is not known if this is always the case.

Corrupted waveforms can be restored by moving them to another viewport, then (optionally) back to their original location.