Entity Reference - Filter Criteria

On updating to current version (3.5) Views output is truncated on a view using entity reference. The view uses Filter Criteria based on an Entity Reference, with two groups. The filter aims to list records based on the existence of relevant items in the referenced entities. The first filter group tests to see if referenced entities exist within a data range ( start/end date >/< now). The second group tests to see if there are any relevant open ended items. On updating Views the behaviour changes - the query seems to break for/at the second filter group. I have tried both filter groups separately and seem to get expected results - it is the presence of the second group which seems to upset things. On reverting to previous version of Views the output is as expected. I can't find the number of the previous version - but I expect it is 3.4, site went live at end of August and was updated prior to launch.

I have appended a PDF with some screenshots which I hope illustrate/explain.