Hi Johnny,
I tried recreating one of the three misbehaving labels and it appeared to
work properly. Then I recreated the other two and all three began
misbehaving again. However, I had not removed the original failing versions
of these two labels - they were simply renamed. The strange thing is, the
original two now worked properly! The failure appeared to follow the labels
with specific names (AcceptanceThresholdLabel and QtyAcceptedLabel). If I
swap the names between the old and new versions of a given label then the
one with the original name is the one that fails. My code switches the
visibility of these labels on and off in response to certain user choices,
but there is nothing obviously unusual about my code.

The simple test form I referred to in my original post was indeed based on
the same underlying query and that worked fine. Recreating my whole form
from scratch is another possibility but this would be a lot of work. It's
actually a subform and potentially I would have to recreate the main form as
well.

Any other ideas for bypassing the internal corruption that I am assuming
exists within my form?

David