S500 blf buttons

i am using the s500 with vpn to fpbx v14. why does the phone reboot for adding a simple blf button pointing to another extension? this doesn’t seem correct. it shold update right away without a reboot and inter-rupting the user.
i am using the save update rebuild option i believe

Are you seeing the same when not connected via VPN?

i dont know how i can test that since all of my phones will be remote as fpbx is in the cloud and vpn is a requirement of the project.