When they change the the location where they burrow it might be a sign that they have left a "deposit" in the hole and want to go some where else.
You might have to go digging for brown gold to confirm.

If you don't find anything then you might want to do a honey soak.

just get a container that has a lid that has a few holes and can be securely put on.
Fill with warm treated tap water to the same hight as the frogs chin and warm it up to 80F
and add 2 to 3 good drops of plain honey and mix.
have a second bath made at the same temp with just treated tap water as a rinse to get rid of the honey.

Put the frog in the honey mixture for at least 20 min. ( now if it is the winter time make sure the water doesn't get below 70F for future ref. )

Trust me they will leave a present.

Hope this helps.

I am not sure but I just did a search for "pachnoda" and it looks like it might have a lot of un-digestible shell parts that might be causing some of the problem.
I would add some large night crawler worms to his diet for a while. Make sure that they have no added scents or coloring for fish bait.
they will act like laxative and provide good nutrition.

Also has there been any major changes in the enclosure tempo or humidity.
just in case you might want to answer the following questions just in case. trouble-enclosure