I'm guessing everyone who had an upgrade on their ACS instance recently noticed that the filtering in the Profiles view has changed, as described here :
Basically, after this update you can no longer apply multiple filters at the same time ! You can either choose ONE of the three filters (first name / last name / email) or ONE of your custom fields. Fitlering on first + last name for example is no longer possible. This is an unacceptable regression of the tool and needs to be rolled back ASAP.
I requested this change to be reverted through Support, who created an enhancement request, but they'll only consider it if enough customers request it. If you agree, please raise a ticket to Support too, and mention following reference : CAMP-48261. I also included the request to add filters based on out-of-the-box fields like mobile number, which is also impossible currently.