Still seeing this in beta 4 as well.

Update: I got around to trying this with 14.3 beta and the problem remains. I had low expectations there, anyway, given there's no mention in the release notes of anything like this.

(Apparently the tolerance defaults to zero, so I guess finer resolution via more frequent updates is probably your best bet.)

This is documented behavior for timers. Timer events are coalesced for efficiency. The delay will increase when the system is busy doing higher-priority things. One simple workaround is to adjust the tolerance - https://developer.apple.com/documentation/foundation/nstimer#1667624 or just update more often (every half-second for better 1-second resolution?). Though, “The system reserves the right to apply a small amount of tolerance to certain timers regardless of the value of this property.”, according to the docs. For SwiftUI it would be wise to update the state (and trigger the view update) only if the actual displayed time has changed when the timer fires. Still, if the system is busy, you’ll notice stutter.

I wonder if it’s “not allowed” to use .bold weight with .footnote style. What happens if you add .bold() modifier instead of specifying a weight? I’d file a bug either way.

... it's a beta. 😕