Here is a seemingly related problem with raise and lower frame.

;; This whole sexp works

(let ((f (selected-frame)))

(lower-frame f)

(sit-for 1)

(raise-frame f))

;; Only the first raise-frame call works

(let ((f (next-frame)))

;; f is raised

(raise-frame f)

(sit-for 1)

;; f is NEVER LOWERED

(lower-frame f))

Bob