Firmware WB.15.18.0007 resolves the issue, see below
A colleague of mine found an issue with the latest HP 2920 switch firmware.
If you create VLANs using the CLI Menu, the switch reboots and the configuration is not saved.
We have reported this to HP, but is currently being treated as a non critical issue as when creating a VLAN via the web interface or native CLI, the issue doesn’t happen.
We have also noticed on this firmware the switch seems to be less responsive. Luckily we had a few units in stock that we could replicate this issue on, and can confirm downgrading to the previous firmware version removes the issue.
A quick cheers to my colleague Marco for finding and researching this issue.
Switch: HP 2920-48G-POE+
Primary Image : 12852982 08/12/15 WB.15.18.0006
Software revision : WB.15.18.0006
Go to the Main Menu
Select (2) Switch Configuration…
Select (8) VLAN Menu…
Select (3) VLAN Port Assignment
Modify the tagging mode for a port
Switch reboots and doesn’t save configuration
Hopefully HP will release a fix for this firmware soon, as mentioned we have recreated this issue in production and test.