Just to make sure effort isn’t focused in the wrong place, but I believe this appears to be more of a Yealink issue than anything else. In the forum discussion that @Marbled referenced, if you start reading from this post forward - g722 Codec Problem - it appears that Yealink and Grandstream, perhaps others, do not negotiate the codec priorities properly.
I say this only because it probably is not an Asterisk issue. The problem most likely lies with the phone manufacturers and their firmware. Therefore, since some effort has been put in place by both the FreePBX team and Yealink to certify Yealink Endpoints, it would be in the best interests of Yealink and the FreePBX team to sort out the issue (regardless of whose fault it is), so that customers who purchase Yealink Endpoints based on the fact they are Certified for FreePBX are not disappointed, frustrated, or worse, when they encounter the problem. The issue has been reported on the Yealink forums, you can find it here: Bug involving codec G722. It has been reported by 2 users in that thread, with absolutely no resonse from Yealink. Likely, the FreePBX team could more easily get the attention of Yealink engineers to point out the bug in the firmware and motivate them to work on a fix.
It is nice to see FreePBX establishing these relationships with hardware manufacturers. It will no doubt continue to make the FreePBX Distro an outstanding product.