Thanks! Sadly, I found this thread only after releasing a watchapp update with a single app target, and looking why Weathergraph users report randomly broken complications. Not even the new watchOS betas fix this :(.

Reported as FB12819243 with a link to this issue.

I tried this as well, and yes, it seems to me that it is necessary to have a different widget extension for watch and iOS.

Same here, happening since iOS 17 & watchOS 10 on both platforms. Users seem to get their widgets randomly damaged like this during app updates.

Ah, the dreaded "Efficiency awaits: Background tasks in SwiftUI" talk. I believe part of the features from that talk are still not implemented as of March 2025 (the talk probably describes features Apple hoped to release by WWDC, but then scrapped - the described .backgroundTask(.urlSession(...)) {} is entirely non-existent), and that the whole talk should be retracted and replaced with a correct info. See https://developer.apple.com/forums/thread/726443?answerId=823711022#823711022