Eyebrows changing color

MAny eyebrows ( that are initially brown) become blond. i can see many ( 7-8 , never had that before, perhaps one during a year) like that and we can clearly see for a 1 cm long eyebrows : 0,5 cm from root is blond - 0,5 to the end is brown. The color changing IS BRUTAL.
So, it can be a marker from one month or 2 or more.
I don't see that in a good sign, but perhaps it can give clues ? ideas ?

This just started happening to me in the last year as well. Curious what causes it... Or if it could be a sign of another health issue...