Apple Watch notification delay after vibration

Delay on Watch after it vibrates.

Prior to upgrading to all the '26' OSs, my watch used to vibrate to notify me of some sort of notification arriving on it, I would look at the watch and the notification would be there.

But since upgrading my watch it still vibrates to tell me there is a notification, but it shows nothing at all on the screen. Only after several seconds does the red dot appear at 12 o'clock, and I can then pull down whatever the notification was. But of course by that time the vibration has been forgotten about, and so I often don't notice the red dot appearing.

I haven't changed any of my notification settings manually since I upgraded to 26, but this delay is making vibration notifications on my watch rather pointless. I have a Series 9 Watch that I bought in January 2024.

Does anyone have any suggestions why this might be happening, or some way of restoring the behaviour to what it used to be like please?