I concur with Mrainey. Check in your NC setup pages, there is a setting for the type of arc center coordinates.
This problem should not 'come and go' if you choose the same machine post each time you insert a new nc object....if you don't crash the program, in which event settings may not be written to disk properly.
Hint: if editing in Bobcad, use 'undo' (in the nc editor) to get rid of the code you don't want. This works a little better than just highlighting and deleting.
If I recall, I think that performing 'geometry from nc' uses your current post settings, so make sure that whatever post you used to post the code, is the same one used to regenerate the toolpath from the nc code. Just a precaution to take if nothing else seems to work correctly.
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)