Not everything is logged, you know? I'm very sure that this isn't logged, doesn't seem like a crash.
Unless I can reproduce this myself I can't even begin to research. You should try an official ROM, and if reproducible there, report on official MIUI forum.
I did a small research and I found something strange. I deleted the dismiss function so the volume dialog doesn't hide. What's interesting, on right rotation for some reason the volume dialog is not clickable, like a ghost. @Igor Eisberg Have you ever met with something similar?
Bug on 0:26