You mentioned it earlier, but what exactly do you mean by my movement speed mod? As far as I am aware I have not released anything that changes player move speed at all. I believe there are several variations of a movement speed mod out there already.
If you do use a speed increasing mod, check to see whether it's the RootTemplate (in Public/(Mod Name)/RootTemplates) or the character (in Mods/(mod name)/Globals/Levels/Cyseal) that is being overwritten. There's a good chance that there will be some sort of conflict if the speed mod changes the Character, since it might overwrite my mod's changes to Player 2. In that case, try renaming my mod's Player.lsb to something later in the alphabet compared to the other mod.