Since it sounds like the standard troubleshooting steps have failed here, I’d suggest reporting this as a bug on GitHub so the patch developers can look into it.
- Download and run Wii U Crash Log Dumper on the console.
- Copy the crash logs from your SD card to your computer and put them all in a zip file. (I forget where exactly the logs get dumped onto the SD card, but the app should tell you.)
- Create a new bug report on the Inkay GitHub issues page. Fill out the report, upload the zip file with the logs, and link to this thread in the additional information section.