It depends on who the vote was from. @sbi-booster manually upvotes comments that add something to the discussion (like this one from you). Those upvotes do not come out of the member upvote balance.

The other accounts upvote comments (at a lower % of balance threshold) for members that have not posted within the last week and have enough balance to get comment upvotes (which vote a lower portion of member balance with a higher minimum).

It's designed so that posts are the intentional primary mechanism for delivering subscribed upvote value, but in cases where members have enough pending upvote balance and aren't actively posting the balance can be partially delivered to comments instead.

In this case, you got both! One from @sbi-booster, and one from your upvote balance.