Support for IE11 was inadvertently broken in GeoMoose v3.2.0. GeoMoose v3.2.1 is a bugfix release to restore support for IE11 (by adding a polyfill that was missing in v3.2.0). As usual, it is available from https://www.geomoose.org/download.html and https://github.com/geomoose/gm3