I have produced a patch for this issue, but beware, while it appears to fix the problem for me, I have little understanding of perl and the existing code base.
> It looks sound, but I have yet to test it. --[[anarcat]]
+
+>> I reviewed a version of this (possibly rebased or modified or something)
+>> that was in the [[todo/osm_plugin_GeoJSON_popup_patch]] branch,
+>> over on the todo page for that branch. Feel free to move my
+>> review comments for it here if you want to split the discussion. --[[smcv]]
+>> [[!tag reviewed]]