Problem with row keys beginnig with characters < than ',' and the region location cache

We currently have a problem the way we design .META. row keys. When user table row keys begin with characters lesser than ',' like a '$', any operation will fail when:

• A client has a certain set of regions in cache
• One region with the faulty row key splits
• The client receives a request for a row in the split region

The reason is that it will first get a NSRE then it will try to locate a region using the passed row key. For example:
Row in META: entities,,1216750777411
Row passed: entities,$-94f9386f-e235-4cbd-aacc-37210a870991,99999999999999

The passed row is lesser then the row in .META.