It's most likely that you have some co-resident edges that are preventing the bevel. Clean mesh and check all the boxes to remove laminar faces, zero-length edges and such. Also, delete non-manifold geometry as that will produce unpredictable bevel results as well. The fact that your poly count went up now insures you have bad geo like zero area faces and zero length edges.

Also, select all the verts and press delete to kill any interior valance-2 verts.

There has to be room for the bevel to happen if you have any spots on what you are trying to bevel with sero length edge then you get a zero offset bevel and just create bad geo.