Apologies, I have only just seen this comment, I cannot seem to replicate this on a fresh set of essentials.
Do you have your scripts exported so that the correct changes can be made to the battle system? I have tested with hotfixes & gen 9 installed and posted in the Pokecommunity server and...
#===============================================================================
# When used against a sole wild Pokémon, makes target flee and ends the battle;
# fails if target is a higher level than the user.
# When used against a trainer's Pokémon, target switches out.
# For status moves...
We've upgraded and improved a bunch of the graphical errors here, there is also a bug with the function for 'Roar' causing it to end all battles in game.