Yesterday I had to correct a razor with near identical symptoms that you describe, except it was 2-3 weeks old & had not seen any tape. For the record I don't use tape either.
The razor was simply unevenly ground & the owner had made it worse. The spine did not "appear" warped & had minimal even wear but the edge bevel did not reflect this. Maybe the use of tape was inappropriate for your razor but don't assume that is so in all cases.