SUMMARY

KDE5 compositor crashes and restarts if hot corner for "present windows" is activated in quick succession.

STEPS TO REPRODUCE
1. Set a hot corner to "Present Windows - All Desktops"
2. Trigger hot corner repeatedly by continuing to push cursor into corner as Present View opens

OBSERVED RESULT

Present view opens. All panels disappear, black boxes appear randomly on screen. Panels reappear and boxes disappear about 3 secs later. Error notification appears saying "Kwin closed unexpectedly" and prompts user to report crash. Desktop effects may fail to restart. Setting "enable compositor on startup" may be changed to false. 

EXPECTED RESULT

Present view opens and closes as many times as the hot corner is triggered.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: Kubuntu 20.10
(available in About System)
KDE Plasma Version: 5.19.5
KDE Frameworks Version: 5.74.0
Qt Version: 5.14.2

ADDITIONAL INFORMATION
AMD integrated GPU in use (Carrizo R5 on AMD A10-9620P) with latest amdgpu driver
OpenGL 2.0 Rendering backend selected (default), but crash also occurs on OpenGL 3.1
I see other similar bugs marked as resolved after 5.14 but this bug still exists in 5.19.