the list A has a lookup field connected to list B in field Title. One of the items in list B has title "CCAA".
On A/ViewAllitems, i can filter in column lookup:listB:Title for every item, except for the "CCAA" = it returns 0 items. I can see that there are items that has lookup value="CCAA". In an A item with lookup field "CCAA", I can select the lookup field and it shows the B/Showites/title="CCAA". So the lookup is working fine, but doesn't filter!
Also, when you press the filter icon, (and shows all the values), this value is the last one, even if there are items with "DA", "FA". On the other hand, in B/Viewallitems, the items are in correct alphabetical order.
I have edit an item in list A, delete/insert the same lookup listB/"CCAA" with the same characteristics.