A Rollei 35 Tessar isn't that old a lens, so you'd expect the coatings to be reasonably good, even if not Multicoated.

I'd double check the camera and lens (and any fiklter if used), I have had issues like this with an enlarger lens and it was caused by internal condensation leaving a fine layer of dust, luckily easily cleaned. You need to shine a point source through the lens looking for scatter, laser pointers do the trick.

Ian