Been folloing the workflow in the documentation for creating flow maps https://helpx.adobe.com/substance-3d-painter/painting/advanced-channel-painting/flow-map-painting.ht...
About a year ago I tried it and noticed it was busted. Now tried it again, still busted. Checked the foums, problems are reported without any resposes by devs. I would love to see it fixed since it a really handy function 😞
Problems that pop up are
1, Using undo somtimes removed a whole lot more than your last stroke/action.
2, Colors sometimes multiplies and cannot be painter over itself.
3, Sometimes a stroke just breaks prior work, even when loading up a file from say, the day before.