Hello Ivan,
There are 2 types of mods: Shooting (Rapid Fire, Akimbo, Auto Burst e.t.c) and Special (Drop shot, Quick Scope e.t.c).
Shooting mods are located on the 1ST slot LED (top left)
Special mods are located on the 2-4 slot LED.
If you want to turn special mods off you would hold down the mod button on the back and then tap the X
If you want to turn shooting mods off then hold down the mod button on the back and press down on the D-pad.
We also strongly recommend reading all the instructions first.
You can access them thru the user account. The picture is attached below
Or by this link below
https://megamodz.com/instructions/ps4
What you refer to as "glitches real bad" is the Dual Trigger Rapid Fire Mod does its job. If you play with single weapons then activate the simple Rapid Fire Mod
https://megamodz.com/instructions/ps4/mods/updated-rapid-fire
Dual Trigger Rapid Fire is for dual-wielded guns to be able to have Rapid Fire on both triggers.