"Bullets" shot from two Pygame sprites combine into a single long line

I have a sprite which shoots bullets. Sometimes bullets also shoot out of invisible shooters.

The switch from opponent to shooter mid-program works but when I want the bullets to shoot in a certain way, with delays between each shot, the bullets seem to become a single line (the purple thing in the image is the bullets):

The mechanic works when it's the opponent shooting, but not when it's the invisible square.

Why is this happening? Is there a small bug I need to fix?

Here's my code:

import pygame
import time
import itertools
import os

pygame.init()
SCREENWIDTH = 1000
SCREENHEIGHT = 650
screen = pygame.display.set_mode([SCREENWIDTH, SCREENHEIGHT])
screen.fill((255, 123, 67))
pygame.draw.rect(screen, (230, 179, 204), (0, 50, 1000, 650), 0)

background = screen.copy()
clock = pygame.time.Clock()
stageon = True

class Spell:

    def __init__(self, bullet, pattern, speed, loop, tick_delay):
        self.bullet = bullet
        self.pattern = pattern
        self.speed = speed
        self.loop = loop
        self.tick_delay = tick_delay

class Shooter(pygame.sprite.Sprite):

    def __init__(self, spell, pos, *groups):
        super().__init__(*groups)
        self.image = pygame.image.load("Sprites/transparent.jpg")
        self.rect = self.image.get_rect(topleft=(pos))
        self.pos = pygame.Vector2(pos)
        self.start_time = pygame.time.get_ticks()
        self.currentspell = spell
        self.speed = 3
        self.ticks = 1000

    def update(self):
        time_gone = pygame.time.get_ticks() - self.start_time
        if self.currentspell is not None and time_gone > self.currentspell.tick_delay:
            self.start_time = pygame.time.get_ticks()
            for bullet in self.currentspell.pattern:
                if bullet[0] <= time_gone:
                    Bullet(self.rect.center, bullet[1], self.currentspell.bullet, sprites, bullets)

            self.currentspell.loop -= 1
            if self.currentspell.loop <= 0:
                    self.currentspell = None
                    self.kill()

class Opponent(pygame.sprite.Sprite):

    def __init__(self, sprite, sequence, *groups):
        super().__init__(*groups)
        self.image = sprite
        self.rect = self.image.get_rect(topleft=(425, 30))
        self.pos = pygame.Vector2(self.rect.topleft)
        self.start_time = pygame.time.get_ticks()
        self.sequence = sequence
        self.spellno = 0
        self.currentspell = sequence[self.spellno]
        self.speed = 3
        self.ticks = 1000
        self.shooters = 0
    def update(self):
        time_gone = pygame.time.get_ticks() - self.start_time
        if type(self.currentspell) != Spell:
           Shooter(self.currentspell[0], self.currentspell[1], sprites) 
           self.shooters += 1
        if self.shooters != 0:
           return
        else:
            if self.currentspell is not None and time_gone > self.currentspell.tick_delay:
                self.start_time = pygame.time.get_ticks()
                for bullet in self.currentspell.pattern:
                    if bullet[0] <= time_gone:
                        Bullet(self.rect.center, bullet[1], self.currentspell.bullet, sprites, bullets)

                self.currentspell.loop -= 1
                if self.currentspell.loop <= 0:
                    self.spellno += 1
                    if self.spellno >= len(self.sequence):
                        self.currentspell = None
                    else:
                        self.currentspell = self.sequence[self.spellno]

sprites = pygame.sprite.Group()

class Bullet(pygame.sprite.Sprite):

    def __init__(self, pos, direction, image, *groups):
        super().__init__(*groups)
        self.image = image
        self.rect = self.image.get_rect(topleft=pos)
        self.direction = direction
        self.pos = pygame.Vector2(self.rect.topleft)


    def update(self):
        self.pos += self.direction
        self.rect.topleft = (self.pos.x, self.pos.y)
        if not screen.get_rect().colliderect(self.rect):
            self.kill()

bullets = pygame.sprite.Group()

opponentgroup = pygame.sprite.Group()

img4 = pygame.image.load("Sprites/utd.png")

ut1 = Spell(pygame.image.load("Sprites/purple-glowey.png"),((0, pygame.Vector2(-1, 1) * 4),
                                                            (0, pygame.Vector2(-0.5, 1) * 4.5),
                                                            (0, pygame.Vector2(0, 1) * 5),
                                                            (0, pygame.Vector2(0.5, 1) * 4.5),
                                                            (0, pygame.Vector2(1, 1) * 4),),4, 1, 400)

ut2 = Spell(pygame.image.load("Sprites/purple-glowey.png"),((0, pygame.Vector2(1, 0) * 5),),4, 8, 400)

op_spells = [ut1, (ut2, (10, 395))]

OP = Opponent(img4, op_spells, opponentgroup)
sprites.add(OP)



def main():
    while stageon:
        for events in pygame.event.get():
            if events.type == pygame.QUIT or stageon == False:
                time.sleep(1)
                pygame.quit()
                return        
        sprites.update()
        screen.blit(background, (0, 0))
        sprites.draw(screen)
        pygame.display.update()

        clock.tick(100)
        if stageon == False:
            return
if __name__ == '__main__':
    main()

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