Hello welcome,
Try to change this…
use GenServer, restart: :transient
# to
use GenServer, restart: :temporary
… to test if it restarts or not (it should never restart). If not, it means on terminate_child, the worker does not stop with normal status, and so it is restarted because of transient.
BTW I usually stop GenServer from within, with a specific message, or under some conditions, but not from the supervisor itself, and not with terminate_child().
