pdf opens in new default-profile window and not on currently used browser window

this issue started when firefox just randomly reset my browser a week ago. whenever i open a pdf in my file explorer, it opens a completely new firefox window under my default-profile. it doesn't open on my currently open/used window. for context: i have two firefox profiles, 1 for work, and 1 is the default-profile which is "personal" anyone know a possible solution to this? or why this happened?