@Import(library=xxx) doesn't work for META-INF/assset/xxx assets from library

I am trying to migrate FlowLogix library to T5.4...
There are a whole bunch of mixins there, that use JavaScript @Import(library="xxx.js").
I used to have those .js in the classpath in the same package.
Now, with the new packaging scheme, I moved them to META-INF/assets/flowlogix.
After this, none of the imports work with the following exception:

Example:
org.apache.tapestry5.ioc.internal.OperationException: Unable to locate asset 'classpath:com/flowlogix/web/mixins/PeriodicUpdater.js' (the file does not exist).

If i change the code to use JavaScriptSupport.importJavaScriptLibrary("xxx.js") it starts working.
Assuming this is a bug, should I file a JIRA? Seems pretty bad to me.

Using alpha-17