Blender Version
Broken: 2.80 Release.
Short description of error
Blender crashes tweaking a strip if you insert a keyframe outside |Start Frame:Last Frame| boundaries of the strip.
Exact steps for others to reproduce the error
-Make any animation/action.
-Push down animiation/action to new strip.
-Edit/Tweak strip.
-Insert keyframe after last keyframe.
-Crash.