A very strange problem indeed …
We have an InfoPath (SP1) form the has a handful of drop-down lists each of which gets its values from a secondary data source. This data source, in turn, gets its data from a web service. Very straightforward and very "working." That is, until it randomly stopped working.
We could not figure out why it stopped as we hadn’t made any major changes. Although, we did frequently update the data connection between dev and deployment servers so we thought the constant back-and-forth somehow screwed up the various XSDs and XSLs that are in the InfoPath solution. Given our assumption, we deleted the data connection and replaced it (no dice) then deleted the drop-downs and the data connections and still no luck. As a last ditch effort we reverted back to an older version of most of the files, deleted all binaries, cleared all cahces. Same behavior! What the ….
After many many many hours of trying different combinations of everything we could think of … I decided that we needed to re-create the view. However, there are well over one hundred fields on this form so doing this from scratch was simply not an option. So, on a whim, I created a new view, cut/pasted the default view’s content to the new view, deleted the old view and made sure the new view was set as the default view.
Now everything works fine. Go figure!