What to do in group assignments where a member used AI?

Haven’t been in a situation like this before but on popular AI checkers their part turns up to 90%+, however these checkers explicitly stated that they should not be used to punish students as they are entirely accurate.

But also is it on the duty of each member to verify everyone else’s work? Since if it does end up being flagged we all have our own Google doc history of what we wrote. Any of you’ll been through this before if so what was done / the impact?