Jason;

I have captured the generated SQL for both versions of Firebird. Except for the cursor name, the two statements appear to be identical.
So it appears to be something to do with the different versions of Firebird.

Here are the two statements:

Firebird 2.0

'UPDATE CT_GRID_COLUMNS CT_GRID_COLUMNS'#$D#$A' SET CT_GRID_COLUMNS.CGC_USER_ID = :CGC_USER_ID'#$D#$A' , CT_GRID_COLUMNS.CGC_GRID_NAME = :CGC_GRID_NAME'#$D#$A' , CT_GRID_COLUMNS.CGC_COLUMN_PROPERTIES = :CGC_COLUMN_PROPERTIES'#$D#$A'WHERE CURRENT OF C4233304011946163'

Firebird 2.1

'UPDATE CT_GRID_COLUMNS CT_GRID_COLUMNS'#$D#$A' SET CT_GRID_COLUMNS.CGC_USER_ID = :CGC_USER_ID'#$D#$A' , CT_GRID_COLUMNS.CGC_GRID_NAME = :CGC_GRID_NAME'#$D#$A' , CT_GRID_COLUMNS.CGC_COLUMN_PROPERTIES = :CGC_COLUMN_PROPERTIES'#$D#$A'WHERE CURRENT OF C3958052873427203'