Merge Resources Error - Conversion failed

Hello,

Since the upgrade to 7.6 (we are now on 7.6 HF7), we have been occasionally getting the error below when we try to merge resource records:

"Merge failed. Converstion failed when converting from a character string to uniqueidentifier"

We don't want to alter anything in our database but this appears to be related to a SQL Convert error. Has anyone else come across this? If so, what did you do to correct it? It does not occur for all of our resource merges, just the odd merge and we can't identify a pattern as to which resource merges will produce this error.

Any help is much appreciated!