Some users still see the old contact number from sfb contact card

Hi Guys,

I recently updated User's A phone number and I noticed that some of the user's from my organization still see the old contact number when checking User A contact card in Skype for business. 

I've already checked the user's contact information from the admin portal, azure ad, exchange and the number is updated.

I just want to check if someone here knows where is this contact number from sfb contact card is based from specifically. Thanks for your help!?