The bulk of your post count was made from forum game posts. Game posts will no longer boosts post count.
Before the forum cleanup, your post count was every post you had made, including game posts.
After the clean up, your post count was every post you had made, minus the deleted posts.
When the posts were restored, your post count momentarily reflected every post you had ever made again.
When all games were moved to the game forum, those game posts no longer counted on your total post count. The number you see now reflects normal posts you have made on regular non-game topics.
When the section for games was created, it was made to NOT count game posts towards total post count. This will help prevent players from spamming in those topics with only the intention of raising post count. This decision was made by the Admin team.