From the iQIES known issues website:
“Some HHA users who use the iQIES user tool to create and submit their OASIS assessments were having their claims Returned to the Provider (RTP) for FISS reason code 37253 for claims submitted between January and April 2020. An issue was identified with the storage of the MBI in the iQIES database which impacted the claims match process. The issue has been corrected.”
“If you are encountering this issue, please resubmit the affected claims to your MAC.”