Wow, we had the total opposite. One UniFi LR on both bands. Kicking 4 (soon to be 5) cAPs to the moon and backUbiquiti and device density was PRECISELY why I moved to Ruckus.
I watched those UniFi WAPs crumble under loads and flat out give up in noisy environments.
I'm sorry, I have checked with firmware update, currently it seems there is software issue, that is going to be fixed in the upcoming versions.