After updating to 21.1.0 this morning, all my brushes with "Build-Up" selected leave a splotch at the beginning of strokes. Toggling Build-Up to off will stop the behavior, but I have dozens of brush presets with this setting on, and I prefer the brush behavior with it on. Using a Wacom Intuos Pro. Rulers are off, and I have not had any issues previous to updating.
We are happy to announce the release of Photoshop 21.2.1 that should resolve this issue.This update includes fixes to some of the top customer reported issues among other bug fixes. See Bug fixes and security updatesTo update Photoshop to 21.2.1, click "Update" in the Creative Cloud desktop app next to Photoshop. More detailed instructions for updatingLet us know how it goes.Thanks,Akash