You need to allow sending CONNECTEDLINEUPDATES to the phones. In chan_sip (sip.conf) this is done with the following two options:
trustrpid=yes
sendrpid=pai
I’m sure the options are similar if using pjsip.
I have used this with Polycom phones with great success. I have zero exerience with Yeallink. Look into that and hopefully you’ll find what you’re looking for.