I created a radial adjustment in Adobe Camera Raw. I selected the brush tool to modify the area impacted by the adjustment. This has worked in the past. However this time, the add to selection brush did NOT operate properly, and it has not since. The add to brush seems to apply in an ABSOLUTE LEVEL. So, where ever the add to the radial adjustment brush is applied, the local adjustment goes to some uniform level. What used to happen is that where ever the add to brush was applied, the adjustment would increase up to a 100% of what ever the radial adjustment was (gradually or immediately depending on the flow setting of the add to adjustment brush). My guess is that I inadvertently hit some setting shortcut. HELP!
-- The add to the radial adjustment brush seems to work fine when used outside the area impacted by the radial adjustment.
-- The erase/subtract from the area impacted by the radial adjustment seems to work fine.
-- The same issue occurs when trying to use the brush to modify a gradient adjustment.
SOLVED IT! ... There is no "density" slider when using the brushes that modify a radial/gradient filter (aka, adjustment). HOWEVER, there is a shortcut to change the density. See: https://helpx.adobe.com/camera-raw/using/default-keyboard-shortcuts.html. If you hit a number other than 0 while using the modification brush the density is adjusted to 10x the number you hit. So hitting 5 makes the add to brush density 50%. This is what I had done. To resolve, the problem, I hit "0" which adjusts the brushes density to 100%.
WISH: Adobe please show the density slider for the brushes used to "add to" or "erase from" a local radial/gradient filter.