Dissipating scrolls are recreated when failing UMD check.

[Nazey]

I haven't recreated or 100% confirmed this, but I used a dissipating scroll of fireball, failed the UMD check, and noticed that I had a permanent scroll of it a reset or two later.  I've been told by others in the chat that they've experienced the same, didn't find a topic so just wanted to make a note.

[TsunamiWombat]

I think this is because you have a chance to retain a scroll after a failed UMD check, so it uses the scroll and removes it from your inventory, then re-adds it. The re-added version is probably the baseline/normal version, and thus doesn't fade.