I did some more tests and now I'm very sure that the voltage is just reported
wrong when using UVD, and not being actually that high.
I also jumps to reported 1.1V without any pstate adjustments or overclock,
while the ASIC's default maximum voltage is actually 0.986V.
Maybe the UVD got its own voltage of 1.1V, and that is sporadically reported
instead of the core GPU voltage when UVD is used?
Anyway, not really important since it's just a little glitch and not a real
problem. :)