Why are the threads in this forum dissapearing so much faster than the other forums? I am currently only seeing 3 threads(after posting this one, there will be 4)

Looks like this particular board is forgetting the "Show" settings and is only showing the last day's posts on default. If you go to the Store Forum's topics page at the bottom is a dropdown called "Show" and it will have Last Day selected. Change the dropdown to something else and click the Show Threads button and the posts will reappear for that time period.