I apologize for the redundancy of this issue, but I have explored all the information I could find over the past couple days and have yet to find a solution to what seems to be a very simple task.
I am attempting to clip a larger landscape layer to a smaller clip layer in QGIS. The resulting layer contains the attribute column of the source layer, but no features. I have run the geometry validity test on both layers with zero errors returned. I have ensured both layers are of the identical CRS. I have experimented with expanding the extents of the clip layer to overlap those of the landscape layer. Everything I have tried results in the same empty layer. The same issue exists when attempting to perform the intersection operation. After experimenting with other layers, I have determined the issue to be with the landscape layer and none other. HERE is a link to the project files so anyone may explore them further.
EDIT: I took another look at the OGR error log and it repeats the error: "Feature geometry not imported (OGR error: Attempt to write non-polygon (GEOMETRYCOLLECTION) geometry to POLYGON type shapefile.)" for what I presume is every feature to be created in the clip output, but is not due to whatever this error means. Anyone care to shed some light on this?