**System Information**
Operating system: Windows-10-10.0.19044-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1650 SUPER/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 472.12
**Blender Version**
Broken: version: 3.0.0, branch: master, commit date: 2021-12-02 18:35, hash: `rBf1cca3055776`
**Short description of error**
Intersect (Knife) with Exact method triangulates some faces (not flat faces - idn how their call exactly)
**Exact steps for others to reproduce the error**
* delete default Cube
* create Suzanne
* enter edit mode
* create plane
* with the plane selected, run {nav Face > Intersect (Knife or Boolean)} - Exact method (by default)
* look at the faces near Suzanne nose, they turns to triangles
* {F12833334}
* add a Subdivision modifier
* look at the vertex near Suzanne eyes, because vertices on eye and on cheek are at the same coordinates, they became connected
* {F12834138}