I have found that sometimes the "Pause until found image" action glitches and does not find the image present on the screen. It's not a matter of the fuzziness needing to be adjusted, or the image not being clear enough. One moment it works fine; the next it doesn't. The reason I believe it to be a glitch is because no matter how much adjusting I make to either the fuzziness or inserting a new image, it still doesn't work. The only thing that gets it working properly again is duplicating that action and deleting the original. Literally, by copying and pasting the glitchy action, the pasted version works properly.
Attached is a screenshot of two identical actions (the top one being the original, the bottom one being the duplicated one), where the original returns false and the duplicate returns true.