thanks for the answer.
Yes, I can reproduce the situation.
No, I didn't re-install firmware without keeping settings; I'm a user and not a firmware tester, I spent hours to configure the router and don't want to loose this configuration just for a test. If this would be significant, means the data structures changed from 00.06.08.03 to 00.07.00, Teltonika should have provided a note marked as important on the web site with the firmware downloads.
Please contact RnD for more information about taking over the configuration when installing the 00.07.00 with respect to the described error.
Thanks and BR