Problem with input in Shugaku puzzles

[jrunning]

Very often in a Shugaku puzzle when placing a futon it will appear shaded red, and when placing another futon the red futon either partially or fully disappears. This problem has been happening on the puzz.link site for a few months. Here is a GIF of the problem:

This issue may be related to #61, however it happens very frequently in every Shugaku puzzle, however unpredictably.

[robx]

Yes, I think it's the same as #61, but we can keep this issue open instead. I also see it now and then, and have no idea what's happening.