Mouse click requires double click to enter input if "Set Input Mode Game Only" used

Mouse click requires double click to enter input if "Set Input Mode Game Only" used

Regression (no) issue (does) occur in 4.12.5

Notes The first box selected will light up correctly the first time it is pressed following the repro steps. All other boxes require a double click to light up.

1. Open Editor (Blueprint Puzzle Project)
2. Open Level Blueprint
3. Event Begin Play
4. From Event Begin Play>"Set Input Game Mode Only">Target = Player Controller
5. Compile
6. PIE
7. LMB one of the puzzle boxes on screen
8. LMB a second box

Results
The first box lights up. The second box requires multiple clicks to light up.

Expected

Both boxes light up after a single click with LMB.