Apple Intelligence download stuck at 100% on Mac

"Downloading support for Apple Intelligence" has been stuck at 100% 'forever' - every time I've tried it, every few months, for the past year. I've wanted to try Image Playground, but every time I've tried it that app says "Downloading support for Image Playground. Once downloaded, Mac will be able to..."

What I do:

I turn it off via the button: Apple Intelligence in Settings->Apple Intelligence & Siri ->Apple Intelligence

Delete Siri history (just in case it matters)

Turn on Apple Intelligence button again

It immediately says 100 % complete... as below, but Activity Monitor show < 100 bytes/second of network, and 98% idle cpu.

What can be done to reset this?

(System details are after the screenshot.)

Platform: MB Pro 14-inch Nov 2024; 24GB memory; 1TB Storage. Plugged in to 120V, battery @ 100%.

Now up to Tahoe 26.3.

Purchased from Apple for California, US

Language settings: English, including Siri

[If it might matter, I have translations settings for French, Italian, German, and Turkish;

and keyboards for Bulgarian-Standard, Serbian (Latin), Greek, and Turkish - F]