Assuming the former, I'll explain what I believe is happening. Also not clear if you're saying this happens when NMM is open and use Vortex at the same time, or if you were just stating the issue started happening around the time frame of when Vortex came out. RE 2: It wasn't clear if the issue you have for this only happens in FO4 mode, or if that happens in SSE mode too. 圎dit may give you insight into which mod is in the wrong place for tweaking your plugins.txt to quickly resolve it. If you have 圎dit 4.x.x you could try to open it up with your load order set in the order that NMM doesn't like and try to open the whole order as it is.
HOW TO MOVE MODS FROM NMM TO VORTEX HOW TO
Then when NMM tries to deal with it, they're in the wrong place and NMM isn't sure how to deal with it so it just disallows ordering. Early on I found this usually to be from things trying to sort. I found the cause of this is usually another program improperly sorting the plugin files externally causing the issue with NMM. This isn't really an issue with NMM as you didn't use NMM to put them in the wrong place. Any files that aren't in that list then get auto sorted to the best guess location and that usually solves it for me. If it did happen that it somehow got glitched up like that, I keep older load order lists to be imported for quick resetting to a previous state. If this ever happens to me (did once, was a broken mod from the author), I go through the whole order just checking which files require what masters and make sure they're not screwed up in the wrong order. RE 1: This usually happens (that I've encountered) when somehow a master got placed after a plugin that required it, or if 2 files somehow were saying they both need each other as a master. Issue 2) NMM locks up for some time when you change the load order through Vortex. Issue 1) You can't manually change the load order inside NMM.
![how to move mods from nmm to vortex how to move mods from nmm to vortex](https://cdn.appuals.com/wp-content/uploads/2020/07/6.-Download-Previous-Version-of-Vortex.png)
Neither issue appears to be a bug in NMM, which I'll explain below.