This is going to be a challenge for me because I have a TN monitor and I tend to make these calls at night where the darkest parts of the screen are fully visible. If a playtester like yourself points out a particularly bad spot like this though, that's a big help because it's hard for me to notice in a regular playtest. I might try lowering the brightness on my monitor sometimes and playing with the evening sun shining right into the room to make it harder to see, lol.
Thanks for playing, glad you liked it!