Adobe Campaign Classic
When searching on recipients using the Advanced filter option that recipients could not be found.
This turned out to be due to the Advanced filter in build 9032 forcing case-sensitivity when performing queries.
The only option is to use other filtering methods, or to ensure that the capitalization in the advanced query matches the record that is being looked for.
Additionally NEO-23240 was created to review this issue and was determined to be working as designed.