During the course of creating complex geometry I was being ‘bugged’, pun intended, by inaccuracies.
This caused me to look closely for User Errors and eventually home in on the first stage, in this case, creating a Circle 100mm Radius.
Initially there did not seem to be anything awry but the project in hand still displayed inaccuracies at an early stage.

All Snaps were in the Switched On position before creating the Circle:

Zooming In close to the Centre of the Circle/Bottom of the Vertical Radius Line:

After several attempts to move the Radius Line, to coincide with the Grid Vertically and Horizontally, my efforts were rewarded. Attention then shifted to the Top of the Vertical Radius Line:

Prepared to accept User Error this was repeated on several New Files, each completely from scratch.
All presented the Circle Circumference being offset to the Left and following setting the Centre on the Grid the Top of the Radius Line is always displaced approximately 0.4mm to the Left.

Attacking this situation from a slightly different angle, it was sketched as shown:

Subsequently Trimmed:

Resulting in, the apparently horizontal line is part of the Circle with the Vertical Radius Line extending beyond it:

Circle Centre is misplaced:

The apparently Vertical Line is part of the Circle and the Horizontal Radius Line extends beyond the Circle Circumference.

Opening the following shapr. File the Bottom of the Vertical Radius Line was found to have reverted to a similar offset position that had previously been corrected. This occurrence was without any input from me. After correcting the position the Point was Locked.
It is also noted, at extreme Zoom In level, that again the Top of the Vertical Radius Line extends beyond the Circle Circumference and that the Dimension Line is Split and displays a gap near the Topmost Arrow.

CircleBug(s)?.shapr (108 KB)

Given the simplicity of this Sketch I assume that it will also be reviewed/investigated by creating a similar New File?