Monsters reset to normal when loading a save game

From DoomWiki.org

Strife, like Doom before it, modifies the speed properties of monsters when certain skill levels are selected at the start of a new game. Doom does this in Nightmare! skill only, where the demon moves and attacks twice as fast and most monsters' projectiles increase in speed. Strife makes certain monsters move and attack at half speed in Training skill, and makes Acolytes move and attack at double speed in Bloodbath.

These changes are made only when beginning a new game. Unfortunately, this does not include loading a saved game from disk after having quit the game. This means that it is impossible to play through either Training or Bloodbath skill with the intended monster properties for those respective skill levels unless the player finishes them without exiting. Otherwise, the player will find that all monsters have returned to their normal behavior as observed on skill levels Rookie, Veteran, and Elite.