Tried submitting a bug report, but it made my game crash. Ironic.
So... my medium armor passives seem to be broken. For days now I've been unable to gain any speed increase from a dodge roll (though it used to work). I'm wearing full medium with all medium armor skills completely filled in at V1.
Also, in recent days (the last 2-3) I've noticed that I'm consistently running into out of stamina. When I first became a vampire I couldn't run out of stamina if I tried thanks to the drain, but suddenly it was all I could do to keep it above 10%. I've now discovered why - or at least part of the reason, as I suspect there are other broken passives as well (actually, the ones that are working are probably easier to list..).
Wearing full medium armor, I opened my stat screen and saw that my regen was around 90 (with 12 more lost to overcharge). I then selected two of my seven medium armor pieces that had health enchants on them and removed them. Doing so should have lowered my regeneration due to the loss of two medium pieces (if the passive was working correctly) but avoided any loss from a reduction in overall pool that would occur with stamina enchants.
Upon inspection of my stat screen with these two pieces removed.. my regen had gone UP to 110 (with 54 more lost to overcharge - I know, holy overcharge!) Putting these two health enchanted medium pieces back on raised it even farther, as expected.
In short - the medium armor stamina regen passive seems to be deactivated for some undetermined reason, and has to be reset by reequipping your gear. If I had to guess - when gear breaks it stops counting for the passive, and when repaired it stays flagged as inactive to the passives. Haven't tested it, but that's my guess anyway.