Hello tonygamble,
Aqua Mail itself doesn’t control how Samsung Watches handle notifications, so the watch will only alert you when Android sends a full, active notification. That “Pop-up screen” option essentially forces Android to treat the notification as high-priority, which is why the watch then receives it.
We appreciate you taking the time to describe the steps. Even if this issue hasn’t come up often, your explanation may definitely help other users who run into the same situation on Samsung devices.
Enjoy using Aqua Mail.