Row ID BUG - Rollup

I have a multiple relation its been working for months. Orders Table to Items Table showing the items who have the same order number of the order.

Orders Table is over 2000 rows.
Items Table is over 10000 rows.

suddenly there is a bug although the relation brings the correct rows, the rollup of the relation is returning a count of 0 RowIDs. If I switch the rollup to item name , the correct count comes.

any idea what has gone wrong with the Row IDs?

Consolidated in the thread below.