Hi Olga - it is normal for operations that involve intersections with surfaces (like curve projection or surface/surface intersection) to be calculated to an accuracy level of 0.001 units.

It looks like you have probably zoomed in quite a bit there in your close up view, and if you draw a line between those 2 points you should probably see that distance is smaller than the 0.001 tolerance value.

So that is not unusual that things can get to be off by that amount, when you join pieces later on into a solid, it will allow joins to happen between pieces that are up to 0.005 units apart, so that is not necessarily going to cause any problems...

What is your final goal for this?

If you are trying to gouge out a piece, it can be easier to do it with a boolean operation rather than individual curve projections.

That would look something like this - draw a line to close the curve, and join it together to make a closed outline.

Select your cylinder, run Construct / Boolean / Difference:



To produce this result:



- Michael