Does pygame have a bug or am I dummy?

bug.py

import sys
import pygame

FPS = 30
WIDTH, HEIGHT = GEOMETRY = 420, 360

screen = pygame.display.set_mode(GEOMETRY)
pygame.display.set_caption('Bug')

blocks = (
    pygame.Rect(WIDTH // 2, 0, 60, HEIGHT),
    pygame.Rect(WIDTH, 0, 60, HEIGHT),
    pygame.Rect(0, 0, 60, HEIGHT), )
speed = pygame.math.Vector2(-10, 0)

time = 0
clock = pygame.time.Clock()
while True:
    clock.tick(FPS)
    dt = clock.get_time()
    time += dt

    for block in blocks:
        block.x += speed.x * (dt / 100)

        if block.topright[0] < 0:
            block.x = WIDTH

    background = pygame.Surface(GEOMETRY, pygame.SRCALPHA)
    background.fill((0xff, 0xff, 0xff, 0x99))
    screen.blit(background, (0, 0))

    for block in blocks:
        pygame.draw.rect(screen, (0x99, 0x00, 0x00), block)

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    pygame.display.flip()

nobug.py

import sys
import math
import pygame

FPS = 30
WIDTH, HEIGHT = GEOMETRY = 420, 360

screen = pygame.display.set_mode(GEOMETRY)
pygame.display.set_caption('No bug')

size = 4
w = 60
blocks = [
    pygame.Rect((WIDTH + w) / size * i, 0, w, HEIGHT) for i in range(size)
]

speed = pygame.math.Vector2(-10, 0)

time = 0
clock = pygame.time.Clock()
while True:
    clock.tick(FPS)
    dt = clock.get_time()
    time += dt

    for block in blocks:
        block.x = math.ceil(block.x + speed.x * (dt / 100))

        if block.topright[0] < 0:
            block.x = WIDTH

    background = pygame.Surface(GEOMETRY, pygame.SRCALPHA)
    background.fill((0xff, 0xff, 0xff, 0x99))
    screen.blit(background, (0, 0))

    for block in blocks:
        pygame.draw.rect(screen, (0x99, 0x00, 0x00), block)

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    pygame.display.flip()

vector2.py

import sys
import pygame
import math

from collections import namedtuple

FPS = 30
WIDTH, HEIGHT = GEOMETRY = 420, 360

screen = pygame.display.set_mode(GEOMETRY)
pygame.display.set_caption('To ceil or not to ceil?')

Block = namedtuple("Block", "position rect")

size = 4
w = 60
blocks = [
    Block(
        pygame.math.Vector2((WIDTH + w) / size * i, 0),
        pygame.Rect(0, 0, w, HEIGHT)) for i in range(size)
]

speed = pygame.math.Vector2(-10, 0)

time = 0
clock = pygame.time.Clock()
while True:
    clock.tick(FPS)
    dt = clock.get_time()
    time += dt

    for i, block in enumerate(blocks):
        if block.rect.topright[0] < 0:
            block.position.x = WIDTH

        block.position.x = block.position.x + speed.x * (dt / 100)
        if i % 2:
            block.rect.x = math.ceil(block.position.x)
        else:
            block.rect.x = block.position.x

    background = pygame.Surface(GEOMETRY, pygame.SRCALPHA)
    background.fill((0xff, 0xff, 0xff, 0x99))
    screen.blit(background, (0, 0))

    for i, block in enumerate(blocks):
        color = (0, 0x99, 0) if i % 2 else (0x99, 0, 0)
        pygame.draw.rect(screen, color, block.rect)

    for event in pygame.event.get():
        if event.type == pygame.QUIT:
            pygame.quit()
            sys.exit()

    pygame.display.flip()