I hadn't played Skyrim for a while and decided to start a new game a few days ago. I installed a handful of mods (Helgen Reborn, Falksaar, and a couple of follower ones).

The first time I levelled up, I noticed that right after choosing my perk, I'd already gained progress toward level 3. That didn't make sense, because I'd levelled after a successful lockpick, not while in combat when a few skills can increase at once.

After that, I noticed that every time a skill increases, it counts multiple times toward the next level. Also, my skill increases seem to be on steroids. I whack someone eight times with my sword and my one-handed skill goes up.

I removed all the mods, so all I have now are the official DLCs, including the high res mod, but the problem is still there.

Is there anything I should check in a config file, or will I have to reinstall? Did anything change in the last patch or two that could be causing this problem?

You should post your load order, inluding the one's that you uninstalled, someone with more experience will probably know exactly what to do.

For now...Not a fix but a work around that might work. Try installing a mod that slows down leveling > save > uninstall the mod. See if that fixes it. If not, just leave it on and see if the mod is working like it should.