I'm not sure if this is from this mod, though I can't think of what else would do it. I got hit by an ice bolt and my character has yet to run again. He can only walk. If I hit the ALT key he crawls. I fast traveled to several places and walked around for quite awhile. The slow effect has yet to wear off. When making the light affect last longer, you didn't increase the slow effect as well, did you?

I've been using Balanced Magic but I think I'm going to switch to this!

I saw you were able to fix it by yourself according to your post on Nexus. Nice.

Anyway, things like this can't happen, so I'm trying to identify if this can really be an issue with the mod or simply a rare bug. I'm noticing there are some functions you simply can't trust in the Creation Kit, so I'm trying to modify the slow effect to avoid these bugs.

I don't know that I would call it a "rare" bug, as it seems to happen to me on a fairly regular basis. After fights with ice-throwing mages, I have a very strong tendency (over half the time) to come away permanently slowed unless I'm able to kill them before they can get more than one or two spells off. When I get stuck with a permanent slow, speedmult is often negative, but not always; the last time, checking a couple minutes after the fight was over, "player.getav speedmult" showed me at -46.

I've been fixing this with "player.modav speedmult" to get me back up to where I should be, which isn't always 100, as I'm also using Imp's More Complex Needs in "complex" mode (which applies (small) speed modifiers to speedmult based on your hunger/thirst/nutritional/long-term-fatigue status) and Battle Fatigue and Injuries (which applies wound penalties any time you take a lot of damage in a short time; wound locations are randomized and leg injuries can reduce speedmult by up to 20). So there's a definite possibility that this may be due to a bad interaction between multiple mods which all affect movement speed.

I just uploaded version 2.9 to Nexus. A fix to this slow effect issue included. Also a change to dual casting.

This issue is pretty hard to track, even more when we see more and more mods out there changing the player speed. To solve this I was obligated to make the player very resistant to slow effects. I don't thing however this is really an issue, since enemy frost spells drain a lot of stamina and are pretty strong against melee characters already.

I just got back to my mage character and noticed you reverted the changes to Soul Trap. It no longer has a projectile and no longer slowly damages targets that have been soul trapped. I assume this is a mistake, otherwise I'll be very disappointed.

Edit: Also, Dragonhide seems entirely too short in duration. Considering how long it takes to cast the spell, 30 seconds doesn't seem worth it. Either make it a spell cast with a single hand so you're not a sitting duck while casting, or increase the duration.

Unfortunately I had to leave SoulTrap as in vanilla because if I change its effect, then Acquisitive Soul Gems will not work. And this mod is a must have IMO. I believe all players will prefer to have their soul gems fixed with ASG than having a DoT in SoulTrap (even though the DoT was indeed nice). Anyway, I recently added Haunt exactly to fill the DoT style in Conjuration.

Regarding Dragonhide, I'm just trying to make sure it does not become overpowered. Someone can cast it, say, just before opening a door, wait 10 seconds for the magicka to return, then still enjoy 20 seconds of half incoming damage for free. Increasing the duration is a valid option, but I'll have to think of some kind of drawback then.

Why not simply make a patch for Acquisitive Soul Gems then?

The reason I want Soul Trap to have DoT is so I can more easily acquire soul gems from random things in the woods by simply casting the spell once and having it both kill the target and trap the soul. On that note I'd recommend adding higher level soul trap spells that have increased DoT in additional to the default one. Though, that might be asking too much from the Conjuration School.

Anyhow, thanks for telling me about Acquisitive Soul Gems.
I don't like it because I can't prepare for (a significant) battle by casting it beforehand, and I don't want to do it in battle because standing still makes you dead. One of the points of alteration spells is that they're supposed to be long lasting.

I would prefer an alternative of having the spell cast with one hand and take much longer to charge (6-10 seconds).

Edit: Well I modded it to do that, but unfortunately the spell charging animation is only 4 seconds long, then it loops back to the beginning after that. How annoying. It seems the best solution is to simply increase the duration.

I uploaded to Nexus a version where Dragonhide lasts 1 minute, but costs more to cast. Increased cost is a way to make up for the long duration, but not the best. I'll eventually come with a better solution and a nicer drawback.

For now, hope you enjoy the longer lasting armor