Endless loop with animation sequence

I’m not sure how I came to create this crash but I suspect it came from accidentally pulling a zero length sequence into a montage - but my attempts to recreate are failing. Unfortunately I had a fever much of last week and my memory is not great but I suspect that actually AllowLooping was true, the AdvanceType was finished, the sequnce length was zero and it got stuck.

In attempting to recreate I hit another critical error in the same code:

[2015.04.14-16.37.06:728][761]LogWindows: === Critical error: ===
Assertion failed: bPlayingBackwards ? (CurrentPosition <= PreviousPosition) : (CurrentPosition >= PreviousPosition) [File:D:\BuildFarm\buildmachine_++depot+UE4-Releases+4.7\Engine\Source\Runtime\Engine\Private\Animation\AnimSequenceBase.cpp] [Line: 596] 

This is triggered by adding a notify to a new (empty) animation sequence and is different to the original loop.

Repro on second issue:

  1. Go to asset manager
  2. Create new asset
  3. Animation assets → Animation Sequence
  4. Right click on notifies and add particle notify
  5. Crash (for me, 2/2)