I have a field using a regular expression setup as follows:
\d\d-\d\d\d\d\d
it is for a project number. (12-12345) it all works fine and well. The only issue is when you want to do a search by field in the client, it will not find anything using the field with the regular expression in it.
I double checked the metadata and verified the data in the field. I even tried searching by template and that would not work either. The field constraint shows up in the search dialog correct but will not work. Not sure if this is a bug or if I am doing something wrong.