Changing which SFX you are viewing does not always change which SFX is edited by the shortcut keys (for the number of ticks per note, at least). So trying to use the shortcut keys can cause a different SFX's ticks per note to change, which is undesirable.

I am presuming this is because a previous SFX has been selected, and the selection has not been updated to the visible one either when the current SFX was changed or when a shortcut key is pressed.

Sometimes it seems to work fine, then sometimes the bug occurs - I am unable to determine the exact sequence to reproduce it.

pico-8 0.0.0i