minified-es5 fails to "load" / correctly handle defective pdf-files

[pfeldbaumer]

Configuration:
latest master / beta 2.4.456
minified-es5 build
various (chromium) based browser-versions (from .49 to .81)

Steps to reproduce the problem:
call pdfjs.getDocument(path_to_invalid_pdf_file) with minified-es5 pdf.js and pdf.worker.js
use e.g. any text-document as "path_to_invalid_pdf_file" (so a valid file, but no pdf-document)

Expected behavior:
PDFDocumentLoadingTask.promise should get rejected with an InvalidPDFException as parameter

Observed behaviour:
code throws an (unhandled) exception "Unhandled promise rejection TypeError: Cannot read property 'message' of undefined"

In current minified-es5 builds calling .getDocument(path_to_invalid_pdf_file) does not correctly "work", it leads to:
Unhandled promise rejection TypeError: Cannot read property 'message' of undefined
at main.js:...
at lib/pdf.min.js:22:64582
at MutationObserver.n (lib/pdf.min.js:22:69954)

instead of rejecting the promise on the PDFDocumentLoadingTask.

This happens with any "invalid" pdf-file (e.g. a text-document instead of a "real" pdf), loading a "valid" pdf however works absolutely correctly (with any version, also minified-es5).
Using a generic-es5 build produces the expected result (an InvalidPDFException is thrown).

The problem itself however seems to originitate in (minified-es5) pdf.worker.js, because using minified pdf.js with non-minified pdf.worker.js behaves as expected?

ps: did not test with es6 (minified)..