Looks like its a longstanding ‘issue’ with mustache.js but…

It would be great if there was the mustache merges would speakup when the merge variable doesn’t exist.

Long standing open issue says mustache.js isn’t going to add the feature. Add option: Warning on unknown variables · Issue #599 · janl/mustache.js · GitHub

Apparently https://handlebarsjs.com/ is a mostly drop-in replacement.

And there’s a mustache.js validator add-in of somesort. mustache-validator - npm

I guess I’m just venting. Spend a couple hours ‘troubleshooting’ DLRS rollups when I just hadn’t hit the checkbox to include the rollup-field in the model…