Any search form that calls "performFind" and has a "date-find" tag will not persist but it will give correct search results.
For example, If I go to Order -> Requests and search using any of the date fields, the result will be correct but the field will be blank upon returning results. This behavior affects only dates.
I suspect the main offender here is a bug in performFind service or one of the services it calls (prepareFind or executeFind). I believe that the "queryStringMap" does not contain the date-find fields in its returned value. I did not look heavily into the code but I think "fld" types are not persisted in-between requests.