Im not sure in which version it appeard, now im on 1.8.
I older versions when there was some syntax error in html it was catched on build level, so in my console i was able to see whats wrong. Now i noticed that in case of such sytax error i see everything ok in builder on client when template is loaded i see error like :
Uncaught Error: Cannot find module './upsell.html'
at makeMissingError (modules-runtime.js:232)
at Module.require (modules-runtime.js:251)
at Module.moduleLink [as link] (modules.js:344)
at upsell.js (app.js:2784)
at fileEvaluate (modules-runtime.js:346)
at Module.require (modules-runtime.js:248)
at Module.moduleLink [as link] (modules.js:344)
at index.js (app.js:2773)
at fileEvaluate (modules-runtime.js:346)
at Module.require (modules-runtime.js:248)
Which gives nothing usefull and you have to go through whole html file lookig for what is wrong. Do you observe thing like this?