Cannot send SMS to phone number with punctuation

My address book, as synchronized from my computer, has phone numbers of the shape, say, `0176/123456`. When trying to send an SMS to such a number, it failed. It also failed for `0176123456`. It would only work for `+49176123456`. A bit later I had a second instance of this problem, but here `0176123456` would have worked. So it seems to be related to punctuation. I hope there is a fix that does _not_ involve going through all my phone book contacts. I did not test the effect of spaces. Might be related to https://together.jolla.com/question/28603