ERROR at line 1:
ORA-06502: PL/SQL: numeric or value error: character string buffer too small
ORA-06512: at "MAPGUIDE.MAPGUIDE_PERSONS", line 59
ORA-06512: at "MAPGUIDE.CREATE_MAPGUIDE_TABLES", line 114
ORA-06512: at line 1
You need to debug the issue to see what statement is actually failing and for what data. I do not see any reason why migration from UTF8 to AL32UTF8 would cause such error provided the data is the same. So this it either an issue caused by a new data pattern and not really related to the migration or some very rare circumstance.