I have several tips and questions for you. I have a ton of experience with Find Image, but I can't say that I know everything about it.
If we could see your Find Image action or condition it might be easier for us to help. For example, we might spot an action parameter that you're using that is causing the search to fail.
One troubleshooting approach is to always enable the "display" option in the Find Image action or condition. And here's a tip: you don't even have to run the action, you just leave it visible in the editor window and if Display is checked off you will see exactly where it sees all copies of that image. In fact the actual fuzz factor number is displayed over each found image. That helps to set the correct fuzz factor value. It's really cool how that works.
Another technique when I use Find Image is to turn the Engine off and on again. Sometimes that helps. For all I know, you may not have rebooted the KM Engine in weeks. That may not be the case, but I can't tell if it's the case for you. So I have to suggest it.
Another technique I use for this problem is to re-capture the image and place it back in the Find Image action. Sometimes this fixes it. I have no idea why.
Find Image works best with multiple colours and fewer solid colours. Your images have a significant quantity of solid colours. If you have something a little more colourful an inch to the left or top of the images you are searching for, that could help a lot. One time I tried writing code to report to me the locations of all the squares of an empty chess board, and it was not able to do that because it really was not able to find solid colours very well. one of your image almost looks like a chess board. I see online there are some images of these apps and some of these apps have coloured icons in part of their interface. If you provide a wider image showing the fuller page rather than just the piece of the image you are searching for, I may be able to give you some helpful advice on this.
Some apps have choices of colours for the user interface (dark, light, and sometimes more). Are you willing to try a different colour option and test it that way? I'm not saying that's the correct solution, I'm just saying that might help with troubleshooting this.
P.S. I was successfully able to search for and find the images you posted. So that means under the right conditions those images can be found.