I asked a question, and someone replied with an decent answer, so I upvoted their answer. A minute later, I discovered there might be some inaccuracies with their answer, so I un-upvoted their answer. A few more minutes later, I finally concluded the answer was correct, and tried to re-upvote their answer, but the site said my lack of a vote was now "locked in". How is this possible? It's not showing I voted at all...
You cannot change your vote ~3 minutes after you cast the first vote, unless the post is edited.
This is a feature by design:
To help curb "tactical-downvoting," we've changed a couple things with up/down voting:
- reduced the time window where you may undo a vote
- started the time window on the first vote, even if it is now deleted (your use case)
So, the clock starts ticking on the first vote you make - you get a few minutes in which you may alter it, but then it's locked until the target post is edited.