Sidebar: switching to powersave before entering suspend is meaningless, the CPUFreq governor is irrelevant in standby/suspend.
(In fact, for interactive use-cases, there's a strong case to be made for actually switching to *performance* before suspend, as on some SoCs, this will allow the device to actually enter suspend faster, as well as resume faster, too. That does imply setting it back to a more reasonable governor post-resume, though
).
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As for the actual issue, if you're actually seeing stale *new* reads, I could somewhat understand PM screwing with it for a while, but it *should* eventually automatically jog itself back into shape :?
EDIT: i.e., I'd try polling after a much larger delay on wakeup (and/or a couple of tries).