Btw, I use Firefox myself. And I did not notice any issues. Though I don't pay to much attention to my post counter.
In any case, if there are issues in the forum software, its SMF (simplemachines), and issues must be resolved in that project, and then when we eventually update they will be resolved here.
There are one or two changes we made on the original, such as the "select" and/or "+" button for code blocks (I am not sure which one or both...).
But the counter is done by the smf software.