"if the parents got the EIP I & II, they will not qualify for the EIP payments?"

Nope. Did you go to the IRS links and read the articles there, and work through the dependency wizard?

"Was a dependent in 2019 as they did not work"

First, 2019 is Moot. Second, worked or not, has nothing to do with Dependency. That is why you should use the IRS interactive wizard for dependency and even the dependent worksheet would be helpful.

"Why is the return now showing as changed and removing the EIP payments?"

That's a different issue entirely. Read this announcement:

https://proconnect.intuit.com/community/proseries-tax-news-updates/discussion/proseries-2020-produce...