I have discovered that a field formatted as 'Phone' and international will only allow numbers that do not include spaces. To try and get over this I tried formatting for 'Number' instead but this also does not allow spaces between numbers.
In my experience some people will put a space between the area code and the main number and if that is done the form generates an error. This therefore necessitates a tool tip instructing the user to not add any spaces. Somehow this seems too controlling and it should surely be possible to add a space without getting the error.
I have version 4.4 currently and do not know if this behaviour has been changed in later versions but if anyone knows a way to allow spaces in phone numbers I would be very interested to know. I suppose formatting the field as single line text would probably work but an option to allow spaces in phone numbers would be great.