If I recall other reporting correctly, ARM has stated both Nuvia and Qualcomm had a license to develop derivative designs based ARM's IP (with different terms and different royalty rates), but they did not have a license to transfer their derivative designs or produce derivative designs that had been developed under a different license by a third party.
Qualcomm has taken the stance that there are actually no transfer restrictions, and thus there's actually nothing against designs being moved between different ALAs with different terms and royalty rates as long as you have an ALA.
I'm not a fan of either of them, but based on the broad-strokes descriptions of the license it sounds like ARM has a reasonably decent case, and Qualcomm's requires some improbable loopholes or oversights?
And I feel like this whole mess could have been avoided if both sides were willing to work out a deal on a transfer fee, but Qualcomm didn't want to pay anything and ARM wanted to keep getting the full licensed core royalty, and neither one was willing to accept less than all of the possible money.