Text messages (SMS) sent to a contact displayed as sent to another contact

[PHuba]

After sending a Text message (SMS) to a phone number from my (Outlook.com synced) contact list, I realized it was recorded and displayed as sent to some other (wrong) contact. I could determine this is happening when the phone number syntax contains space (such as "+32 495 99 88 77"). In that case, the reverse lookup (I guess) is not matching as it apparently looks for a number without space (in my example "+32495998877" or maybe just "+32" picking up the St matching contact).
When I send a SMS to a contact with phone number with no embedded space, the problem does not occur.
W10M 10.0.10586.107, Lumia 950
Any idea why? How to fix?
Regards, Pierre