Scanning of Home PLMN while latch to other network in Home PLMN

[ltecity]

Case:
Mobile is latched to home network. At the same time intra circel roaming is also allowed for one of other network in same PLMN.

Home network is lost and mobile latched to the network with which intra circle roaming is allowed (First time manually and subsequently automatically as at first time the PLMN was in forbidden list of SIM, which become allowed after first successful registration).

Now Home network coverage is restored.

Question - Even if good coverage of ICR roaming provider network is available (Where mobile is latched) whether mobile will switched to home network? If so what triggers network switch over.

Read Case for Details.

Is this functionality depend on core vendor (like E*******, NSN etc)