Found @strarsis solution here. For excluding assets from file hashing.
Though this looks like a known issue using Leaflet with webpack and css-loader.
When investigating the img src, it looks like it’s looking for a relative URL:
<img src="marker-icon-2x.png" class="leaflet-marker-icon leaflet-zoom-animated leaflet-interactive" alt="Marker" tabindex="0" role="button" style="margin-left: -12px; margin-top: -41px; width: 25px; height: 41px; transform: translate3d(329px, 256px, 0px); z-index: 256;">
So even if you’re able to exclude these files from hashing, it won’t work. 