Whenever I try to buy something from Talvas Fathryon, he shows me that he has absolutely nothing to sell:
This happened after I told Talvas to part ways with me (leave as a follower), and when I visited him at the Tel Mithryn Tower. I'm pretty sure that it's been more than 48 hours (so his merchant inventory should have reset by now), and I also don't recall buying out all his items (so he still should have a few items in his inventory). I have previously hired Talvas as a follower and remember viewing his non-empty merchant inventory before.
I would like to buy stuff from him as the "Talvas Fathryon" UESP wiki article states that "Talvas' store contains an extensive collection of standard Skyrim Destruction and Conjuration spell tomes, as well as tomes for additional spells added by the Dragonborn DLC".
The notes of the "Talvas Fathryon" UESP wiki article state that: "if you hire Talvas as your steward, his trade inventory will become inaccessible". However, I have not hired him as a steward.
I am playing on the PC and with mods (mod list here).
How do I make Talvas sell stuff again?