I have 2 daybloom farms in a UFO with a minor relay of (normal) spreaders:
1 spreader in the middle of each circle, each aiming at another spreader between them and closer to the ground, with the latter funneling to a mana distributor with 2 mana pools, one with a dispersal spark above it.
They all have potency/resistance rainbow lenses. Re-aiming them doesn't change anything, but replacing them does.

Daybloom circles / spreader relay

Spreader / mana distributor + pools

Mana distributor + pools

A screenshot would be great. What version are you running? Logs please.

Version 101, screenshot has to wait because leaving the house right now

Did it happen once or does it happen on random intervals?

It's at random intervals. They don't start shooting again after a time either, only after being replaced. I haven't tested this with redstone spreaders and toggling them off then back on.

I've since restructured my farms and none of the spreaders has frozen except when I placed one within what I assume to be a spreader's range for collecting from generating flowers.

Hm. Interesting, doesn't seem like there's any good pattern for reproducing it so I'm closing it for now, but I'll keep it in mind if I happen to come across it.

See issue #407