Artificially Low Bounce Rate in GA - Double Tracking issue

I have been testing our landing page tracking using the “Google Tag Assistant” because I noticed our landing page bounce rate is showing < 5% in GA, and has normal rates for the main, non-landing page domain sessions.

The results show the following message "This page has two interaction hits within a short time window. The page might have two hits that always fire on page load, which can cause an artificially low bounce rate. "

Is see we had both GA event tracker and GTM set up over two years ago, does anyone know what purpose the event tracker serves and whether that would cause double tracking with GTM?

Link to Event Tracker Script Below
https://jsfiddle.net/4vz0euym/

Screenshots from Google Tag Assistant Below

Screen Shot 2020-07-12 at 2.37.26 PM1669×769 90.2 KB