BUG in board view: Wrong count of tasks per column if grouping has been applied

If I apply a grouping in the board view, the count of tasks per column shows one too many tasks: If I have one task in the column, it says the count is 2. If there's no task in a column, the count is 1. Once I remove the grouping, the count is correct again:

Edit: After trying it with with an example where the grouping gives me more than just one group, it seems to be adding +1 for each group there is.