Here’s what I end up with when encoding the .hdr file to .png using the code from @sebavan (https://playground.babylonjs.com/#95Y4D7#10) with the splice fix:
With this picture, the rendering is ok, assuming you set myLightmapTexture.isRGBD = true. Applying tone mapping is a must too.
Note that you have some flickering in your scene because of z-fighting: there are some geometries that are duplicated, it seems.
[EDIT] For a basis of comparison, here is the scene using the .hdr file, with tone mapping enabled: