S3 Q&A: Will I have to stop working during the SEVIS transfer?
If you're working on OPT, or on CPT from your current school, yes: that permission ends on the release date, and you can work again only from the CPT start date on your new I-20. Many students arrange a short unpaid leave with their employer for those days. Your consultant plans the release date so the gap is as short as your school's timeline allows - never by working through it.