I along with others had GlusterFS issues after 4.3 upgrades, the failed to dispatch handler issue with bricks going down intermittently.  After some time it seemed to have corrected itself (at least in my enviornment) and I hadn't had any brick problems in a while.  I upgraded my three node HCI cluster to 4.3.1 yesterday and again I'm running in to brick issues.  They will all be up running fine then all of a sudden a brick will randomly drop and I have to force start the volume to get it back up.