Why Does My Shaw Calendar Change Notification on Reminder?

My girlfriend and i have had BB Q10's, now we have a Passport and a Priv. With all devices, when sending Calendar appointments between devices, using Shaw, the time on the reminder always gets changed.

This is not a problem with the devices, as we have successfully sent Appointments from a Yahoo account to a Telus account, and the time for the reminder was not changed.

I know the obvious remedy is to use the Yahoo and Telus accounts, but we are cancelling the Telus, as we have switched to Shaw as our internet provider. So we would like to get the Shaw accounts working correctly. Sometimes using Shaw even affects the creator of the Calendar event.