I’ll admit I might be experiencing something like the Mandela effect here but further down in the wikipedia page under Designs, Colors it lists “Old Glory Blue” as either Pantone color [https://www.google.com/search?q=PMS+282C](PMS 282C) or [https://www.google.com/search?q=PMS+281C](PMS 281C), and perhaps the latter has been adopted more in the past few decades. The material the flags are made of could also have an effect on how the color is perceived.
It may be more likely that the color casting of older film media doesn’t represent the true colour of the object at the time
This.
I’ll admit I might be experiencing something like the Mandela effect here but further down in the wikipedia page under Designs, Colors it lists “Old Glory Blue” as either Pantone color [https://www.google.com/search?q=PMS+282C](PMS 282C) or [https://www.google.com/search?q=PMS+281C](PMS 281C), and perhaps the latter has been adopted more in the past few decades. The material the flags are made of could also have an effect on how the color is perceived.