iPhone 14 using email with comcast

I have a distribution list with 37 names that I use.  It worked initially but then started messing up.  The first name in list goes away and the group name is rearranged with an exclamation mark circled at beginning of To field and another circled exclamation mark and > at end of list.  

I have to go to outbox and delete the exclamation mark references and add back the first name. 

I’ve checked all names and they are good.  Any ideas on how to fix?