Well, the bad news is, my eyes completely skipped over the runtime issue in @tdfairbrother’s initial post; the good news is I noticed the issue when I was comparing outputs to typescript plugins. 
New versions of the following packages have been published:
@rescript-graphql-codegen/lib@rescript-graphql-codegen/graphql-tag@rescript-graphql-codegen/operations
Bumping operations should fix both issues. If using a custom implementation of graphql-tag, see the wiki for the new fragmentWrapper config parameter.