Similar issue here, except Repeat By doesn't have any results populated. My existing packages work as normal, but if I try to add or edit relationships, I can't in the LEDD because it's required, but the field doesn't work. Have to go back to Classic and not touch it in Lightning. Bug? My guess is our two issues are the same, but yours happens to have Row already populated.

@ccg-administrat and @AdamJass  - can you both submit a Support case? You each have a separate issue, and we'd like our Support and R&D teams to review. We have seen this before, and we're working as quick as we can to get a new Drawloop version released to address these. We'd like to confirm our work will resolve your issues, if not we'll work quick as we can to find the root cause and release a fix. 

I will do that, @SamSysum . Nintex's support site has historically been strange and hard for me to navigate. Similarly now, I can log in here, but it brings me to the Customer Central login page when I click to create a Support Case, and it won't take my credentials, saying there is no contact or account. I tried resetting my password, successfully reset, and it still won't take. Similar issue as before, if I recall. I will email nintexsupport@nintex.com.

Working with support, they identified the problem and fixed it. This article details the fix, in case it helps others. The package requires that all picklist values in the Copy Type field of Relationship object are available, and 2 were not for me, for some reason. 
https://community.nintex.com/t5/Technical-Issues/Drawloop-LEDD-Related-By-and-Repeat-by-options-not-populating/ta-p/121882