Set Playback End will cause a sequence's upper bound to be inclusive.

FSequencer::SetPlaybackEnd calls SetUpperBound which creates a TRangeBound with the default bounds type, so the end frame will be inclusive instead of exclusive.

1. Create an editor utility widget 
2. Add a button, and assign an on clicked event
3. In the event call Get Current Level Sequence, and Get Playback End, then print the result
4. Set the sequence's desired tick interval to the same as its display rate
5. Use the timeline UI, or end bracket to set the playback end
6. Run the utility widget and click the button 

RESULT:

The printed frame will be one higher than expected.