You can handle this by manually adding the student back to the course they were removed from, exporting the student's grades, then removing the student! If you add the student by a CSV upload, they won't even get a course invitation notification, so you may be able to get it done quickly enough that no one even notices. 🙂

Our institution used to have this issue regularly, but we switched our enrollment management system to stop removing students from courses and instead just making them inactive. Solves all sorts of problems. I don't know if that's possible with CAMS, but I do recommend inquiring about it!