@El12 - Are you close to the border? It may initiate by accident if less than 20KM closer to the border.
Does your phone have AT&T, T-Mobile or Verizon (Though Verizon isn't roaming partner)?
For most users just ignore it but if you want the tower to not connect to USA please turn off data roaming.
Or even just selecting "Public Mobile" as the manual network selection will make it go to TELUS Network with no US towers.
But PM Also has no roaming pay per use fees. If you don't buy the add-on or a Canada-US plan - no US service other than receiving SMS and MMS.
