How a USB3 device is detected over a USB2 one?
Micro-AB USB 3.0 ports are usually OTG ports, and require proper ID pin assertion to work in USB host mode. And since your devices do operate at least as USB 2.0 devices, it means that the ID pin is wired correctly in this "adapter", ID = ground. So everything should be all-right.

However, many so-called "adapters" (in $1 range) are made with brutal violation of necessary impedance matching requirements for USB 3.0 signaling rate. Many are made with loose wires soldered between the u-AB plug and Type-A receptacle and then molded into the form. I have seen horrible impedance deviations in this kind of dongles, up to 150-200 &Omega; in differential impedance, so even USB 2.0 devices would behave flaky. 

For USB 3.0 the SuperSpeed link detection comes first. The link gets the termination detected and proceeds with link training. But the transmission quality requirement for SS rate is 10-fold tighter than for HS, and there is no surprise that some adapters fail USB3 link training with horrible number of unrecoverable errors, the USB3 interface gives up, and the port/device reverts to USB2 mode.

My experience with adapters was always a gamble, you never know if the device is good or not. You never know. There are good adapters on the market, but you need to electrically characterize them using high-priced equipment (Time Domain Reflectometer, TDR). Or you can investigate the quality of adapter by using longer cables/extenders, and find the limit. In you case the adapter is very bad, you need to procure some other brand/shape, or request USB-IF certification data on the device.