Significant fixes for kernel crashes and intermittent "Offline" status reports that plagued earlier builds.
upgrade https://dl.ui.com/unifi/firmware/U6-LR/6.7.8/firmware.bin u6-lr latest firmware
Have you updated your U6-LR? Check the community forums at community.ui.com for user reports on the very latest build before hitting "Upgrade All." u6-lr latest firmware