Custom Filter Ignored In Report

I have a simple report that I'm trying to get to report (and summarize) only records where a number field <> 0 by creating a "Custom Filter". It seems from all the different things I've tried, ZoHo report generator wants to ignore the Custom Filter. It does also utilize an "Auto Filter" to select a month/yr at run time, and this aspect works, but it's still listing records that should not be included according to the Custom Filter that is saved with the report.

I feel I must be missing something but are there known issues where Zoho backend will ignore a Custom Filter saved with a report?

Thanks

Robert