You are correct, that is not a proper use of the construction tag.  If the road isn't not completely closed, we want it left open for routing.  If the construction is expected to last 6 months or more, it might be worth changing the lane count and add a maxspeed:practical , or adding a construction landuse around the area.

If the schedule is not known, leaving it in the non construction state and adding a fixme and/or a note in the area is a better way of handle the issue.

