The <touching color> block won't detect sprites that have effects like “brightness” applied on them, whether or not you take the effect into account when picking the color for the color block

Example: see the pong in this project. https://scratch.mit.edu/projects/196323057 the red “solid” blocks aren't detected when darker.

My browser / operating system: Ubuntu Linux, Firefox 66.0, Flash 32.0 (release 0)