Firefox opens link in wrong app

When clicking this link, Firefox opens the Organic Maps (OM) app, rather than Google Maps.

When looking at the default link settings for Organic Maps (Settings > Apps > Organic Maps > Default open), I notice that only is opened by default in OM, and should be opened by the Google app (which in turn opens Maps, I think). Opening the same link in Chrome does in fact open Google Maps.

Perhaps I once selected OM the first time I opened a google link, but now I can’t seem to reset it. I found an old article mentioning in about:config, but that setting isn’t present on my installation

Does Firefox keep its own list of default apps, and if so, how can I change this?