RPG IV pgm dump

We had an RPG IV pgm blow up yesterday afternoon with the following msg:

The target for a numeric operation is too small to hold the result (C G D
F).

We know why the pgm abended - we had an invalid value in one of our
database fields.

But we also had the following msg at the end of the dump:

Error occurred while retrieving variable data.  Dump terminated.

Although we were able to locate the invalid field, in the past (RPG III),
when we had the full dump, we would have been able to locate the problem
much faster.  Does anyone know what causes the terminated dump?  We talked
it over here, but know one really knows.  Compiler options?  Debug options?
Change management system?  Any ideas would be very much appreciated.
Thanks.