I left my previous job and got another job then applied to transfer my H1B but the application / paperwork was sent after 60 days have passed since my last day of employment, while I'm still in the US.
I got the approval email from USCIS and now waiting on official document in the mail. Does that mean I'm in the clear?
You will need to see whether USCIS approved the petition as an extension of status or not. You can't tell that from the email notification. But it's likely that it did because typically if it didn't, the company would have received a request for evidence on that issue first. Of course, you should speak with your employer's immigration attorney about this as well.
