JavaScript Slowdown Problem

Not sure how this happened, or exactly when, but some time in the last few months this issue has appeared where certain JS is loading on one of our sites VERY SLOWLY.

So slowly in fact that we are getting heavily dinged by Light House/Google Page Speed Insights. Here is a screenshot:

Attachment 7118

I'm minus a Drupal 7 developer right now and fixing this particular type of problem is beyond my capabilities as I do not know how to diagnose its origin. Any help in figuring this out appreciated.

Also, if you know someone of quality who can fix a few issues for us on the back end, please PM me! If I hire them and they do a good job, I'll chip in a finder's fee of some kind!