User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:91.0) Gecko/20100101 Firefox/91.0

Steps to reproduce:

automatic upgrade to version 91.3.0esr on Win10 64bit OS

Actual results:

After upgrade to version 91.3.0esr "smooth scrolling" not works properly.

Expected results:

The cause is the setting of values

general.smoothScroll.mouseWheel.durationMaxMS 200

and

general.smoothScroll.mouseWheel.durationMinMS 50

Older versions have

general.smoothScroll.mouseWheel.durationMaxMS 400

and

general.smoothScroll.mouseWheel.durationMinMS 200

Values was changed as solution Bug 1418822,
so solving one problem should not create new ones.
I strongly recommend returning to the original values,
because the new setting degrades the function
"smooth scrolling".

This was discussed in bug 1680077 and we decided against it for the reasons described there. You are always welcome to apply the previous settings to your local installation.