I was finally able to find a way to work around the issue. Rather than using the step by step, I went directly to my schedule C and income line item 1b. There is a grey button for "quickzoom" to add a form 1099 NEC. Once you click that you can modify prior year forms or add new forms. After you add a form then right below Box 1 where you enter the dollar amount you see "Schedule C" and if you double click the blank then it allows you to choose a business to associate with this 1099. For whatever reason, doing this does not have the issue of removing the business activity fromt the list of choices (I have two businesses) and all my 1099s are in that relate to this activity (this schedule C). My guess is the glitch has something to do with going to the new 1099-NEC vs. 1099-MISC but I tried deleting all my old 1099-MISC forms and starting fresh and I still had issues so going to the forms was the only thing that worked.
