My hunch is that when they moved the parameter dials out into a separate thread (dumb idea if ever there was one) they passed across only the internal FP representation of the number. Then when it necessarily gets converted back to real numbers you get this error. With P4 and PP the original real number is presumably still accessible, so the rounding error isn't displayed. As diolma points out the error will exist internally anyway, because the rendering engine (preview or final) will use the internal FP number. So you can safely ignore the error. But it is every annoying given that the dials are effectively broken in P5 and P6 on Windows due to that separate thread design screw-up, err, choice. It bites you when you are forced to make small changes via typing in decimal place increment changes: you end up often having to re-type the whole number, rather than just the digit you were changing. Can we start a lobby for CL/EF to put the dials back inside the main Poser thread so they can again work correctly and responsively? If they did that we could finally all drop P4?PP and stay exclusively in P6.