Sleep and other low-/suspended-power modes can cause such issues with "hotswapped" items like USB devices, if they're plugged in when a normal power state resumes. It's much more of a problematic "nuisance" with swappable drives than with USB gizmos, lol.
If nothing is plugged into the intermittently "problematic" USB port then it's basically a poor power design on the motherboard's USB controller(s). Each USB controller (and each USB port) should allocate required power as required when required. But all too often these things are logically isolated but not electrically isolated so some USB devices will hog all available power while others languish in an intermediate half-unawake state.
As stupid as it sounds, I find a lot of USB problems can be avoided by just plugging the devices into different ports, moving them around until a "perfect" configuration (or a better idea about how the onboard port/power allocations are prioritized) becomes apparent.
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