Did you actually get a charge?

For future reference, if you set your phone to manual network selction, pick Koodo from the list that populates, your phone will only connect to Koodo. And if you turn off data roaming in your phone settings, it’ll at least prevent a roaming charge on background data use. 

No, I assume I'll get one though since it popped up. Do I just flag this again when I get the charge?

I would wait until then to be sure. It's possible that data usage triggered it so I'd guess it did. And then a rep can be flagged to look into it