Solved! Go to Solution.
That's a legit message from TELUS. The link is identical to the one on all the roaming messages from 7626 that I have received in the past when traveling in the US.
You may not have crossed into the US but the cell tower signals coming from just the other side do not magically stop at the border. If your phone decides that signal is the strongest one then it will connect to it.
It still will give you the alert as soon as hit a US tower, however if you make a phone call or send a text message it would still trigger the Easy Roam charge if it is made from a US tower.
To avoid that happening you would want to put your phone into home only. On an iPhone that would be going into settings > cellular > network selection and turning off automatic and selecting TELUS and on an Android device would be going into settings > Network & Internet > mobile network and turn off automatic and select TELUS.
If you do set home only you will only connect to the TELUS network so if do go traveling and needed to use your phone would have to turn back on automatic in the network selection page.