Assets.loadText() failing for html5 in 2.2.1

I’ve an external text file with a json string with a number of parameters I need to read in. Both Flash and Windows targets work great, but HTML5 is running into all sorts of trouble. HTML5 gives me the message

TypeError: (intermediate value)(...) is undefined

Trying another approach and loading it in binary gives me the message

"Assets.hx:539: [openfl.Assets] There is no asset library named """

Is there a known issue with HTML5 in the latest version? What is this ‘asset library’ that is missing and can I create one? Could the issue be on my end? I’m at my wits end trying to get this working!

[edit]
Using the Loader class instead of Assets seemed to fix most of the issues in all targets. Leaving this up for future reference.

Is there any chance you could whip up a little sample that reproduces the problem, so we can make a fix? Thank you!