What you're seeing is very likely just the natural framing innaccuracy of a rangefinder camera. It is there with your Bessa as well but one doesn't notice so much with film because it's not so easy to compare the picture (on the LCD for digital) with the finder view. Over time, your mind can learn where the picture edges will really fall in relation to the frame lines. Again, this is true for all RF cameras all though some are a bit more accurate than others.
Two lenses that are both nominally "35 mm" can have noticably different fields of view in practice. The FOV of a lens also changes as it is focused from near to far. As such, RF frame lines need to be a bit conservative. These factors are part of the reason SLRs caught on so well...but I still prefer RFs. One has to "learn" each RF camera/lens combo and it's edges.
Cheers,
Sean