Need to stop wonky brush behavior in PSE 2018

[TechSmith1]

I was in the process of colorizing an old B&W photo. My brush stopped behaving normally and started displaying both hue and opacity jitter... which I confirmed I have set to zero.

I double-checked my layer settings, my brush settings (including tablet settings because, though I sometimes use a tablet, it wasn't currently hooked up). I checked my mix modes on both layer and brush. No good. Then I changed brushes - same behavior. I changed sets of brushes and chose one - same thing.

I rebooted PSE2018. Same thing.

I rebooted my PC (Windows applied an update). Then I restarted PSE2018. Same behavior, both on the original .psd and on a fresh document.

How can I do a hard reset on brush properties, as I assume that's what I need?

Attached is output from a 70 px hard round brush.

[Peru Bob · Accepted solution]

Try this:

Restore default preferences
Preference settings control how Photoshop Elements Editor displays images, cursors, and transparencies, saves files, uses plug‑ins and scratch disks, and so on. If the application exhibits unexpected behavior, the preferences file could be damaged. You can restore all preferences to their defaults.

Note: Deleting the preferences file is an action that cannot be undone.

Do one of the following:

Press and hold Alt+Control+Shift (Mac: Option+Command+Shift) immediately after Photoshop Elements begins launching. Click Yes to delete the Adobe Photoshop Elements settings file.
Go to Edit > Preferences (Mac: Photoshop Elements > Preferences > General), click the Reset Preferences on next launch button, and then click OK. When you restart Adobe Photoshop Elements, all preferences are reset to default settings.
A new preferences file is created the next time you start Photoshop Elements Editor. For information on a specific preference option, search for the preference name in Help.

from here:

https://helpx.adobe.com/photoshop-elements/kb/preference-file-locations-photoshop-elements.html

[TechSmith1]

Thank you! That worked!

[Peru Bob]

You're welcome.