Contact app fails to call using international format (+) in numbers

The “Dial” button in the contacts app on mitel (aastra) phones only works with numbers containing digits only. The international sign (+) which replaces two zeros results in a failure when attempting to dial. This is annoying if you have contacts from an active-directory using this format on it’s entries. Can someone confirm that this is a general bug/issue? Just want do ask before opening an issue…

Mitel/Aastra 6867i
Phone Apps
Contact Manager 14.0.3