Do not force zoom level

I use IPGV&M on a Search API view. No markercluster, auto-box is set but when displaying the map there is a zoom out effect: the map is first displayed with a correct auto-box zoom, but one second later, it's zoomed out. I figured out it's zoomed out to the zoom level I set in Leaflet Mapbox configuration. If I set a bigger level, I get a zoom in instead of a zoom out. At the end, the zoom level is always the one set in Leaflet Mapbox conf.
I could get rid of this problem by commenting out 'zoom' => variable_get('leaflet_mapbox_zoomlevel', 2), in leaflet_mapbox_leaflet_map_info(), but this is only a workaround.