problem printing small tags

I am having difficulty encoding the epcs on small tags. I have tried manual tag and rfid calibration, tried factory reset and manual calibration again and calibrating from the Zebra Setup Utilities application. I am using 2 sizes of tags - 2 inch by 1 inch and 1 inch by 1/2 inch - all Monza 6. I am using the Link OS package in a XAML application to send the ZPL to a brand new ZD500R printer (V74.20.01Z). The larger tags print and encode just as they're supposed to. The smaller tags behave themselves while printing only - with the exception that the printer skips a tag, prints a tag, skips a tag, prints a tag... When I add the instruction to encode the epc : $"^RS8^RFW,H,,,,^FD{Epc}^FS" or $"^RFW,H,,,,^FD{Epc}^FS" I start encountering all sorts of odd behavior (this works perfectly on the larger tags). Sometimes it skips a tag, prints VOID, skips a tag, prints a tag, etc or sometimes it just spits out a half a dozen VOID tags and sometimes some of those actually have the correctly encoded epcs! Can anyone give me a hint as to why am I getting such erratic results?