In v3.1, you can get multiple or even infinite Modwy.
Steps to reproduce:
1. Soulbound it and upgrade to stage 3 (completed 1500 damage to kith).
2. Talk to Modwy. Have Xoti in party and talk to its former owner.
3. Let Xoti release Modwy's soul from the sword. You get one non-soulbound/non-talking unique superb sword. This is expected, but the original Modwy equipped will NOT disappear.
4. Leave and re-enter this area a few days later.
5. I found the former owner walked toward the left-top corner of the map. I talked to her again without having Xoti in party.
6. I decided to keep Modwy and I got one non-soulbound/talking unique superb sword. The original one on my hand still didn't disappear.
The message popped out tells me that the Modwy is soulbound (to anyone). So, it is strange that mine is non-soulbound.