Apple Watch Siri annoyance setting timer

Before iOs26, if I asked Siri on Apple watch 'Set a timer for 20 minutes', the timer would start running immediately. Since iOs26 (almost) every time I give this exact command, I see that Siri has understood the command exactly as I pronounced is, but I get a follow-up question: 'For how long?' (even though on the screen it shows the exact words I have pronounced: 'Set a timer for 20 minutes'). After answering '20 minutes', the timer starts running.

I've had 1 or 2 occassions when the timer starts running immediately as it did pre-iOs26.

Does anyone have any idea what is happening here? It's very annoying! Something that worked perfectly has somehow been broken.