Currently running Trisquel v.10.0, but it seems that this problem happens for all Debian-based systems. When one selects the "mouth" option during the interactive sections, the cursor disappears after deselecting it. Clicking still works after this happens.
I have tried to replicate this behavior using the Windows version of the game running in WINE (64-bit v.5.0) and in the web version of the game; in both versions, this behavior does not happen.