garlic plants with all different heights

[bower]

The scapes are off, so I'm into the final three weeks or so before harvest of my main crop porcelains. I was very happy with their progress this spring in spite of the wet and wild winter without mulch and the cold and wet spring and summer up until recently. There was one plant that I pulled some time ago - it had a normal sized stem to start with then turned thin and spindly and losing its leaves. I found a white maggot with a black head on the roots, and quickly disposed of the lot. The others seemed fine and they still do look healthy - but once the scapes came out it became really obvious that they are all different heights - many of them are much shorter than the standard height. The short plants are scattered evenly around on all three sides of the bed and throughout as far as I can tell. The same is not true in my back garlic bed which also came up almost two weeks later. I wondered if anyone has seen such a thing, and knew about the cause? I don't know if bulb size will be affected, but for sure I will check all their heights and size of bulb when harvest comes.
I took a pic and marked the tops of cut scapes by getting in close - really hard to pick individuals out, but I believe I have marked the front row correctly just to show how much variation in height. There are three different porcelain varieties in this one bed, and all appear affected in the same way.