This is not an LSPDFR issue but rather a game issue. GTA V has loads of weapons, when you ask it to give you all of them it is too much for the game to handle in one instruction.
My suggestions:
Pick only the weapons you need (e.g. Pistol, Taser, A Rifle, A Shotgun, Nightstick, Torch), then add the attachments you want and then save that loadout on the Save/Load Loadout setting.