When the text plugin decides to load the .js version of a resource (due to useXhr returning false), load errors are not propagated back to error handler of the require call. With the current implementation users of the text plugin are at the mercy of waitSeconds, which will never timeout if set to 0.
The fix seems simple enough: the (delegate) call to req (currently at line 216 of text.js) could simply take onLoad.error as error handler.
Note: while the defect description looks very similar to #133 it is a different issue.