I have 2 pieces of text which are using the exact same font settings to render.
font2 = pygame.font.SysFont(None, 18)
header_text = font2.render("Commodity", True, white)
text0 = font2.render(str(button), True, white)
If you are blitting the text multiple times without redrawing, this will remove the anti-aliasing, because it will be placing partially transparent pixels on top of each other multiple times. I discovered this when programming a pause message for a game.