Yes, if I let the device use the (previous) configured apn from the nvm then I don’t see the issue. So it’s indeed caused by the registering of the ‘new’ apn.
But every time I set a new apn, my application thinks the sim card has been removed for a few moments which is unwanted behavior.
In facct, when the current APN is being used, you cannot change it directly.
To change it, please follow:
AT+CFUN=4 or AT+CGATT=0,
AT+CGDCONT=1…
AT+WPPP=1,1,…,
AT+CFUN=1