I'm not 100% sure what's going on here. I don't have experience with suspending tasks because… well, see below. If you have a reproducible case, please file a bug, including a small test project that demonstrates the issue. I'd appreciate you posting your bug number here, just for the record.
My question for you is, why are you suspending these tasks? Tasks suspension is rarely used and, when it is, it's mostly used to temporarily disable callbacks as part of some sort of concurrency control system. That's because a suspended task can still be active on the wire; all that the suspend does is prevent it making progress internally, issuing callbacks, and so on.
OTOH, if you're implementing a long-term pause (for example, the user wants to pause a download), you'd be better off calling
-cancelByProducingResumeData:
.
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Quinn "The Eskimo!"
Apple Developer Relations, Developer Technical Support, Core OS/Hardware
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