I'm understanding that there is one combo with 10 items, not 10 combos that are cascading.
To me, it can only mean that for one particular list item, there are no results. Create a test query using the fields you're trying to filter and manually input a working value as criteria to validate this query works. Then input the value that doesn't work and see what happens. If it behaves the same, it is as I said.
Is the non-working value an option like "ALL" or NULL?
The more we hear silence, the more we begin to think about our value in this universe.
Paraphrase of Professor Brian Cox.