The plate is made with 2TY with Ampicillin, Kanamycin and Glucose. The plaques that form are small and big on the same petri dish, its got a pretty disproportionate look to it.
M13 plaques are generally pretty small, ~1mm or so. If your plaques are much larger than that I would worry that you might have contamination with some other phage.
Maybe you have 2 or more strains of the virus which produce plaques of different sizes. You can test this by sampling from small and large plaques separately, growing the virus and retesting their plaque size. Do this several times if you want to purify the different variants/strains.
The small plaques maybe secondary plaques derived from the larger plaques. Could shorten the incubation time so these don’t appear, or use a more viscous overlay
Michael J. Benedik The issue is actually different sizes on a single plate, but thanks for your help!