have you recently plugged any of those ports into another switch, because if portfast was enabled then it would bring the Vlan down.
below an extract to look out for:
BPDU port-guard: Version 5.4(1) of CatOS software can monitor whether portfast is enabled on a port. A port using portfast should be connected to an end station, not to devices that generate STP packets called bridge port data units (BPDUs). If the switch notices a BPDU coming into a port that has portfast enabled, it will put the port in errDisable mode.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...