ok, I know what you mean, I tested the 1.4.165, if you use uuu to download images, the timeout error would appear, so if you use UUU download images, and doesn't connect any device, the error message would appear. this is only test uuu -t 0, the same as yours, doesn't have timeout error message
joanxie_0-1671508543981.png
when I use uuu to download images to the board and doesn't connect the board, the error would appear
joanxie_1-1671508701119.png