Normal for Sharp Mobilon 4600 to require hard reset after changing the main battery?

I modded my defective grayscale Mobilon's AA battery holder to work on my color Mobilon 4600. However my 4600 has an issue that makes this useless: Anytime the main battery is removed and re-installed (whether the original rechargeable pack which still works or my AA holder mod), the Mobilon refuses to turn on until I remove the main and backup batteries to do a hard reset.

For others that have a color Mobilon, does yours behave this way as well?

If I need to hard reset the Mobilon each time I remove the batteries to charge them this won't be very useful, though I can probably further mod the AA holder so that it can charge the AAs in the Mobilon, but I'd rather be able to remove them to charge.

Thanks

I suspected the backup battery was weak causing corrupted memory when removing the main battery, even though Windows reported the backup battery as good, it was an old used one. I put in a fresh backup battery and I can now remove the AA holder to charge them without having to hard reset!

Finally I have a color HPC that runs on AAs!