Printer thinks it's done but it isn't

[Bikeracer2020]

The whole STL looks odd to me.

Normally the STL would be just the actual wing I think, I can't see the point in printing the whole rectangle in several layers and then printing the wing profile on top of it because you then need to remove all the excess print rectangle afterwards.

Perhaps print a 25mm calibration cube and see if you can print the full height.
Check the printer profile to see if the figures in the cura configuration file for the X,Y and Z axis correspond to the build volume of the printer.

There does seem to be something not right in the STL, In Orca slicer it shows the first three layers as an alternating diagonal patterns as usual, then for the next several layers the extruder path just goes from corner to corner without actuall moving diagonaly over the print, also looking at each layer after the first three, the diagonal infil does not alternate, it's all in the same direction for each layer.

[alathIN]

The rectangle needs to be there - this is a fiberglass molding plug. The goal is to make an indentation the shape of the wing in a flat body surface. You cut a hole in the existing surface, attach this to the outside, and lay new fiberglass into the hole, resulting in a flat surface with a recess in the shape of the wing. So the rectangle has to be there to provide the surface.

I tried uninstalling Cura, re-downloading and reinstalling, and checked the printer specs (height = 400mm) and got the same result.

So I think this is a problem with the .stl file.
I can model the shape in Solidworks to make the wing part integral with the rectangle instead of being an add-on and see if that helps.

I'll try printing a 25mm cube first as a test.