Vector::WithMagnitude(1) of zero vector! 
Generate::REGEN (for bounding box) took 15720 ms
Generate::REGEN took 31897 ms
Generate::ALL (for bounding box) took 16577 ms
Generate::ALL took 33203 ms
Generate::DIRTY (for bounding box) took 15852 ms
Generate::DIRTY took 32006 ms
Generate::ALL (for bounding box) took 16113 ms
Generate::ALL took 32466 ms

See a linked model below for reproduction. The log is above. The culprit is the step and repeat rotating group. If I apply it (e.g. 20 rotations) to any complex sketch (say 20 construction + 10 actual lines) it slows down significantly so it remains unresponsive for a few minutes

Note: The Vector::WithMagnitude(1) of zero vector! string above is repeated after every line many times. I have omitted it for the sake of readability.

Image & file

• gear-32-2.zip

System information

• Operating system: Linux Kubuntu (plasmashell 5.21.4)
• SolveSpace version: 3.0.rc2+repack1-3

Expected behavior

• Lighting fast overall performance

Actual behavior

• Very slow step and repeat rotating. It also slows down:
• • solid suppression (browser)
• • toggling control points visibility (browser)
• • workplane switch (browser)
• • creation and delete of a sketch in a new workplane (editor window and browser)