Test Plan error on Zephyr Enterprise 7.7

Zephyr's test plan throws the below error on a particular folder. 

Tried to do sync, removed the altID reference but we can't seem to get into this folder to see the test cases due to this error. Respective test execution folder is intact. We are losing productivity as we end up deleting the folder and spend time creating one more. This is a frequent issue with Zephyr 7.7 since we upgraded in late Feb.