Xbox one bl2 and presequel patch differences

My friends and I, installed the whole collection. Fully patched and we can not join each other’s games due to “having different patches”. We all bought same time, installed the same time, started the same time. How are we not all patched the same? There are 3 of us… And we tried all different ways to join each other’s games. How is it possible all 3 of us have 3 different patch levels?