I have rinsed as close as 24 hours prior to having a relaxer with no adverse reactions. There have been members on here (around the time you joined Zora ... and you probably know who I'm speaking of) that have done the same thing with no problem. The reason why I do this is because my new growth gets tangled very easily and it would be a killer to part (just the parting alone would produce intense burning) if I didn't wash close to putting in a relaxer.
Your stylist saying that 'you're hair is too clean and that the relaxer wouldn't process' was totally false. I could see if she said that she refused to do it because of the possibility that you could've irritated your scalp when you CW'd but she didn't. I wouldn't be brave enough to rinse and relax in the same day, however, but I wouldn't think twice to do it at least 24 hours before (now that I use different products that soften my 4a-z texture than I was at the beginning of my hair care journey, I can give it 48 hours and still be able to part my hair with no problems)
In addition, the more build-up you have on your hair, the longer it takes to process. Which is one of the reasons why relaxers don't "take". If the relaxer has too much to get through, then you will end up with
truly underprocessed hair (meaning ... dry, frizzy, and very fragile) -- in this situation, the relaxer was just starting to "touch" the cuticle before the relaxer was washed off.
Also Zora, are you truly underprocessed (see above)? If not, then imho, I wouldn't even bother with getting a corrective. Correctives make a dramatic difference if you are underprocessed, not underrelaxed (if that makes sense). HTH