I think that casting more than one vote on the same post results in all curation rewards being lost
It won't allow you, if you are not casting a higher vote. If its same, it would tell, your current vote is identical to existing, bla bla...
I have experienced this, can't say, if its a bug or not.
no error message is ever displayed here throughout the process of voting and revoting
So I voted this comment first, and it still does not reflect, but then if I vote again, this is what I get.
Yes, that is a different scenario. The problem that needs to be addressed affects posts that have had 1000 or more votes.