Good morning.
Just for fun, I spun up a one-click Discourse app on Digital Ocean to see if I could repo this issue. The forums are running 2.7.0.beta1.
I installed the plugin per the instructions here, and enabled it ‘Site Feedback’. I added in one topic, and then merged it into a topic with no votes and the votes did not carry over.
There are no relevant logs in /logs, and nothing was thrown in the JavaScript Console either.