This is interesting. I'd definitely say that your guess about it having to do with the mods that you have installed is 100% accurate. Mods can be fickle with you if you aren't careful how many you download, which you download, and what combination that you download them in.
I'd start with going into your mod list, and looking through all the mods you have and checking the compatibility they have with other mods. Most mods, or rather, the reliable mods, should have a list of compatible or none compatible mods. They'll also have a suggested load order as well that should be followed as well. Once you go through all that, what I usually do is uninstall mods one by one, and load into the game and test to see if the problem is still there as I go. May take some time, but eventually, you can find the mod that presents a problem.
If you need any more help or suggestions when it comes to mods let me know! Good luck!!
