If you set the scripts to be deferred and async, then the async tag is ignored.
I don't know if this is by design - but I can't understand the use case. Why wouldn't we be able todefer + async js files? The help text specifically indicates "Here there be dragons! Asynchronous JavaScript Execution: Add The async Tag To All Script Tags"
Needs review
4.0
Modifier
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It's likely this issue predates Contrib.social: some issue and comment data are missing.
Patch #2 works perfect for version 4.1, but when updating to 5 or 6 it gives an error, and it is because in this version the parameter that is passed to the asyncJs() function from FilterResponseEvent to ResponseEvent has changed.
I upload the patch for version 5 and 6.