Can't enable l2tp, flagged configuration, can't change device-mode

RouterOS Beginner Basics
1

Hello.
I am trying to enable my l2tp interface but it says:

Couldn't change Interface <l2tp-out1> - configuration flagged, check all router configuration for unauthorized changes and update device-mode (6)

I followed instruction provided on website:
https://help.mikrotik.com/docs/display/ROS/Device-mode

and I typed:

/system device-mode update flagged=no

and plugged out power supply from my board and connected it again but when mikrotik is up it keep says flagged=yes

[admin@MikroTik] > /system device-mode print            
     mode: enterprise
  flagged: yes
2

Something has probabaly triggered the flagged state and that’s why the parameter has been set again to yes. Check for any disabled configuration and review it, after which exit the flagged state with the command you used before

3

All I did before that happened was to add PPPoE configuration because my Internet provider informed me that they are changing the way they authorize users (before they authorize by mac address). After that my VPN to my company (via l2tp) stopped to work so I tried to modify it and then I got message about flagged configuration. Should I try to disable that PPPoE and try?

4

Perhaps try once again to leave the flagged state, and if it has been turned on again, check whether there are any disabled rules, interfaces, etc.

5

factory reset, firmware upgrade, software updgrade - nothing helped, my device still getting flagged
I changed to another similar device and imported all my previous settings and all working good now.
Looks like something wrong with the hardware.