I could've sworn I was due for another ticket by now. I'm one short of the item I want from the forum shop, and I thought it was 5 posts/ticket. Is this incorrect?

Forum tickets are given out randomly. You might be mixing them up with quest points, which are consistently every 5th quest. They're also buyable from the shop search, if you're really in a hurry to get that item though

yeah I probably was. My memory isn't the best lately. Thanks.

This might not be helpful but on average I've noticed its about 10 posts per forum ticket