You can prevent this by disabling the SIM, if you want to.  But as nostr:nprofile1qqstnr0dfn4w5grepk7t8sc5qp5jqzwnf3lejf7zs6p44xdhfqd9cgsppemhxue69uhkummn9ekx7mp0qywhwumn8ghj7mn0wd68ytnzd96xxmmfdejhytnnda3kjctv9ulj6hdh says, it does not mean the cellular modem is communicating with the network.