So ran into a very weird issue.  I had just finished patching our Dev and Test servers to the November 2017 CU.  And after this occurred, any updates to solutions using JavaScript injection was not working.  I’ll describe the problem in more detail here right away, but I want to make sure I give a call out to Trevor Seward.  Trevor blogs from The SharePoint Farm and kudos goes to him for pointing me at the Blob Cache (but I am getting ahead of myself).

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