XF 1.4 The two pages before whatever page im on is gone


Active member
hello, i have a weird problem

lets say i am on a thread with 8 pages....page 7 and 6 will be gone from selection...i can still go to it by pressing next or previous..but i cant click it...now lets say people posted and we hit page 9..now page 6 will show up and page 8 will join 7 and vanish

help please