I hit the Outwitters 2.0 jackpot this time, two bugs in one replay!
The medic FOW bug is still very prevalent and I see it in the majority of games that I play. So much so that I actually expect it, and I play the game assuming that the replay is lying to me about what actually happened the previous turn. The mobi FOW bug is less common, but I've seen it a few times now, and in this case it was both at once.
Based on what I saw the first few turns, the only possible scenario was that he spawned a heavy on turn 3, then a medic on turn 5. That would mean that the pre-deployed heavy was still in it's original location. So I start turn 6 by moving my runner to attack a non-existent heavy. I would like to start playing league games again, but this is why I'm not.
Oh and to clarify, the replay shows and unboosted heavy moving out of the FOW by itself (i.e. not being spit out by a mobi), and it never shows the health increase during the replay. In reality, it was being moved there by a mobi, and it was boosted after it was moved.