This is generally because there are many different VoIP systems out there and some adhere to the standards a little less or 'different' than others, but this is easy to fix.
All you have to do is log in to your VoIP phone/VoIP software and find the setting for 'Caller ID Source'.
For many makes of phones, this will be in their 'advanced settings' menu.
There are generally several options you can choose there and you will have to test which one will work in your case.
For Yealink telephones, we would recommend the 'RPID-PAI_FROM' option.
This should display the correct incoming number and possibly even the name if that is available and your telephone has a display that can show that.
Let us know if your findings are different and/or if you need more help with this.
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