We have an SQLExpress database that I applied a single filter to, and there are records showing that do not match that filter.

The filter setting is against a 30 byte ASCII field, and the criteria is to only select records where this field is not eq "".

There are a significant number of records showing that have this field empty. There are 3 other filters defined, but they are all inactive.

Version 18.2.

Is this some quirk of SQL ?