So in the word list っ and つ are sorted as the same letter. This may be standard for japanese localization, but if you don't have this localization installed you get a different order. The bad thing is that the binary-search method in the bip39 mnemonics tool doesn't work if the list is not sorted. Thus, for example, the unit tests of python-mnemonics fail.
This is my fault:
I sorted the list BEFORE NFKD normalizing it.
Sorting again AFTER NFKD normalizing it will produce the results mentioned.
When I first made the pull request, I was under the mistaken impression that the lists were not to be NFKD normalized, and all NFKD normalization would occur in the apps... but someone corrected me, and I fixed the NFKD normalization of the list... however, it seems the order should have been changed too.
Unfortunately, there are people using phrases generated with this word order.
BIP39's weakness: the checksum depends on the order of the wordlist... therefore requiring the wordlist... but the BIP says "not require wordlist" while at the same time "require check the checksum" (which requires knowing the wordlist lol)
I can understand why ThomasV removed BIP39 functionality from Electrum now...