T58A SfB Phones - Filling up Azure sign-in logs

We have Yealink phones using Skype For Business calling plans. The other day when MS MFA was down I made a change to our conditional access policy, the next day I noticed there were tons of sign-in logs from "Yealink - Skype for Business Certified Phone" in our Azure Sign-Ins page. I reverted the conditional access change but the Yealink sign-ins are still filling up the logs. Each user shows a login every 30 seconds to 2 minutes and it's driving me crazy. Any ideas how to track down what caused the sign-ins to start populating and reduce or stop them?

Screenshots:
https://imgur.com/ug6Zlgz
https://imgur.com/Pg3oK1i