Adobe mad changes in the brush engine and added brush smoothing somewhat like the Lazy Nezumi Pro plug-in does. The is a preference you can use to turn off that string tail. If you still have problems post you action.
How can you turn it off?
Do not know if touy can turn smoothing off you can turn the trail off.
Photoshop can now perform intelligent smoothing on your brush strokes. Simply enter a value (0-100) for Smoothing in the Options bar when you're working with one of the following tools: Brush, Pencil, Mixer Brush, or Eraser. A value of 0 is the same as legacy smoothing in earlier versions of Photoshop. Higher values apply increasing amounts of intelligent smoothing to your strokes.
Pulled String Mode
Stroke Catch Up
Catch-Up On Stroke End
Adjust For Zoom
Prevents jittery strokes by adjusting smoothing. Decreases smoothing when you zoom in the document; increases smoothing when you zoom out.
While using stroke smoothing, you may choose to view the brush leash, which connects the current paint location with the present cursor position. Select Preferences > Cursors > Show Brush Leash While Smoothing. You can also specify a color for the brush leash.
Thanks for the tip. I got the leah for the brush turned off but my action(s) are still now working So frustrated.
Post your actions and state how they fail and which steps fail.
Same thing has happened to me. I have several actions for skin smoothing and most aren't working now since update. I'm frustrated, as well.