K1 sprinkler nozzle pop out

Hi,

I have just installed 6 K1 sprinklers, they are on two different zones, so 3 on each.

Issue is 3 of them the red nozzles have come out when I turn it on. The red nozzles have flown out onto the grass. They have the standard nozzle size in them.

Is the plastic nozzle no good? Or should I be adding a different size for these nozzles?

I’m sorry if this is an obvious question and mistake. Just not done it before.