Email bounced and then invalid due to SF update error

We recently noticed a huge soft/hard bounce on one of our campaigns. Upon further research, I found out SF users made a mistake and updated a lot of emails with .full at the end of email addresses and then reversed it back. (see image) This was done 9/5 and 9/6. When we sent out emails on 9/12, the emails bounced and then got set as Email Invalid. What is the best way this can be fixed? Also, why did Marketo set them as bounced/email invalid if the emails are correct again? Or any insights on this is appreciated. Would love to relay more information to our IT team of the error and what happened to our email campaign.