Are there any situations where an Amateur might be better than a Master

For example, I think you can beat GM Yuri Averbach now

not exactly part of what the OP was asking but i would also mention this

even  class players can beat even GM's at a frequency that may surprise you (of course its  still extremely rare). This usually happens however if the class player (obviously almost always at the cusp of expert) held on long enough to reach a drawish endgame and the GM pushes too hard to try to get a decisive game and messes up. I seen it once or twice in Open tournaments, one of them in round 1!

YES! As an amateur I can tell you I am better than masters at losing games. That is about it though.

Even GM make really stupid blunders sometimes. For example there is a funny video on Youtube called "Eric Hansen Rage Compilation" where GM Eric Hansen (one of the best Blitz players in the world)  has collected his most stupid blunders and his reactions.