Actually, I meant delete and recreate the table using SE14. In normal processing, this table should be empty. It only temporarily has entries during import of transports or support packs, or during an upgrade. At the end of successful activation of imported objects, the entries in this table for those objects should be cleared. So, if you have 31 objects in the table in QAS, but 0 in DEV, then you probably had some prior failed import in QAS. Assuming you don't actually have a problem with other inactive objects, then very likely the only real problem is the presence of this data in the table.
So, try this in your sandbox system to ensure it works and doesn't cause any other issues. Go into tcode SE14. Enter DDXTF as the object name, select 'Tables' for dictionary objects, and click Edit. On the next screen press Delete database table. There will likely be a few warnings and 'are you sure' type messages. When that process is complete, then press Create database table. This should create a new DDXTF table, active and empty, on your database using the DDIC definition as a template.
If that works, and you have a successfully activated DDXTF table with no entries in it, then try running the ST-PI update on your sandbox and see if you get the error you got in QAS. If not, then I would say you have a solution.