Two of the reply-form manifests in Chat AUXC Winlink Forms v2.3.zip point back at themselves:
NC ICS-213 General Message Reply.txt has the line ReplyTemplate: NC ICS-213 General Message Reply.txt
NC ICS-213RR Resource Request Reply.txt has the line ReplyTemplate: NC ICS-213RR Resource Request Reply.txt
A ReplyTemplate: line tells the client which form to open when the recipient replies. It belongs in the initial form (e.g. NC ICS-213 General Message.txt, which already has it correctly). A reply form normally does not need a ReplyTemplate: line at all; when it names its own file, the client follows reply → reply → reply forever. If a reply-to-a-reply is not intended, remove the ReplyTemplate: line from those two .txt files. Winlink Express happens to tolerate this, so it was likely unnoticed.
A fix will be included in next release of RadioMail.