This occurs because the telephone number wasn’t entered by using the E.164 format. Numbers in the E.164 format typically start with a plus sign prefix that’s followed by a maximum of fifteen digits. For example, the E.164 format for the United States telephone number 555-0100 that has an area code of 425 is +14255550100.If a telephone number isn’t entered by using E.164 format in the Office 365 portal or in the on-premises AD DS, it won’t replicate to the Lync address book or it may appear in an unexpected format.
Note Unexpected formatting can also occur when a user has an Outlook contact who has the same number as the Lync contact. This data can sometimes be merged and results in an unexpected format. Disabling Personal Information Manager (PIM) integration can help locate the source of such an occurrence. The recommended action is to remove or change the Outlook contact to match the Lync contact information. Check for essay writing service reviews