Sometimes when I make a slope, I walk on it and suddenly sink in it (like a "quicksand block"). I hope you will fix this bug, thanks !!!

Which version are you using 1.12 or 1.20?

It happened in 1.12.2...And It's very sad to hear that you stopped supporting 1.12.2. Anyway, thanks for your response. I hope this bug will not happen in 1.20.1

Hope so too. Normally this should work. Never heard of this issue before except if your slope is very very long. How long is it (want to test this in 1.20.1)?

I usually make 1/16 slopes (Height = 1 block, Length = 16 blocks)

I found out that this bug usually happens when I go up.

This issue has been fixed for 1.20 in e0907c3. _Doc will try to fix it for 1.12 as well. Not sure when it will be out, but maybe probably in a few days. I will close this issue for now. Thanks a lot for reporting and taking the time!