Notes/Domino 4 and 5 Forum

I have a form with two CFD fields - the formulas differ only in the column looked up.

DR := @DbLookup("";"";"(ECNPages)";SubassemblyPN;4);
@If(DR = "";"na";DR)

The lookup view contains about 150 docs, one for each key.

Assume
That I have several docs all using the same lookup key.
The key exists in the lookup view.
Values exist in column 3 and 4 for this key.

The CFD using column 3 always works.
The CFD using column 4 sometimes works and sometimes displays nothing.

The forms are identical.
(It should be noted that the form with the CFD fields are not editable so there is no way to 'refresh' the oddball docs.)
The key is identical in each of the docs being tested.
The docs that fail to return any value are always the same.
I have refreshed the lookup view.
I switched to a 'NoCache' version of the formula - no change.
I switched from column number to field name in the lookup - no change.
If I run the exact same code as an agent that generates a prompt box, it work.

I am confused. I can understand a lookup failing becuse of the 64K problem - not an issue here.
I can understand a lookup failing because the fomula is wrong - not the issue here.
Bad key? Then the lookup would fail all the time.

Am I looking at defective docs and just need to have the user recreate them from scratch next time around or is there something I am missing?

TIA for any help.

Doug