When you are registered in a network with different MCC/MNC codes to the ones in your SIM, you are roaming unless the MCC/MNC of the network you are registered to is in a list that is stored in a file on the SIM.
In this case two operators with different codes have recently merged, so it is doubtful that SIMs that were created before the merge contain the right information on the SIM to remove the roaming status.
New SIMs should provide the right information. We will try to find a workaround, but meanwhile if you do not want to set data enabled when roaming my suggestion is to ask for a new SIM to the operator.
When you are registered in a network with different MCC/MNC codes to the ones in your SIM, you are roaming unless the MCC/MNC of the network you are registered to is in a list that is stored in a file on the SIM.
In this case two operators with different codes have recently merged, so it is doubtful that SIMs that were created before the merge contain the right information on the SIM to remove the roaming status.
New SIMs should provide the right information. We will try to find a workaround, but meanwhile if you do not want to set data enabled when roaming my suggestion is to ask for a new SIM to the operator.