M900 with M30 ROAMING

Hi everyone, .
I have a M900 multicell system with 3cx v20 on premise.
The firmware is BSV740B102 and HSV740B100
Is it normal that when I roam (with no active calls) with a handset from one cell to another the associated SIP account does not move with the phone but remains in the first cell?

Multicell settings:

Sync Time (s) : 60

Data Sync : Multicast

Auto config Dect tree : enabled

Sip account [...] distributed load : 8

Sip server [...] multiple registration per account : enabled

thanks
Lorenzo