Tell us what you are trying to do?
For several years, we have been using exactly the method in the link below to assign a post author using a frontend Toolset form that creates new posts. We updated to the lastest version of WordPress and of Toolset this week and that custom select field no longer displays on the page.
Hello. Thank you for contacting the Toolset support.
Can you please share problem URL where you added the form as well as admin access details so I can see whats going wrong with your setup.
*** Please make a FULL BACKUP of your database and website.***
I would also eventually need to request temporary access (WP-Admin) to your site. Preferably to a test site where the problem has been replicated if possible in order to be of better help and check if some configurations might need to be changed.
I have set the next reply to private which means only you and I have access to it.