Hard to say really. Because they both operate in the ISM band, there is a possibility of interference. For instance, take a look at this old (2002)
article in EE Times.. But based on it's age, I would guess that current SOCs in handsets probably have radio hardware/firmware that has "other-protocol awareness"
that prevent the device from interfering with itself, but probably do absolutely nothing about interference from/to other devices in the area on the "other" protocol. (That is, other BT devices interfering with the handset during it's use of 802.11, other 802.11 devices interfering with the handset's use of BT, and conversely for both). The protocol standards for Bluetooth and 802.11{a/b/g/n/ac} have mechanisms for cooperation/sharing for devices within their own protocol; but obviously a protocol standard can not have anything to say about something outside of it's own definition.
Then have a look at this
Cisco article about the prevalence of interference in WiFi networks. Together with interop problems, it goes a long way to explaining why you see so many different reports of different kinds of trouble - the ISM band is a wide-open, uncontrolled experiment by the FCC. The fact that a lot of devices and combinations of devices succeed (WiFi is quite successful overall) is not a guarantee that trouble experienced in a particular case is the result of defective hardware or software.
Several generations of Android ago I experienced a problem where many devices on a WLAN were successful connecting to a Linksys WiFi router - and my Android phone would associate and authenticate successfully - but never get a DHCP lease. Sounds like a problem with the Android phone software/hardware, right? Except in this particular case, the problem was resolved by
updating the router firmware, not the phone.
In that instance, it was tempting to "blame the phone" based on nominal behavior of other devices; but that inference turned out to be incorrect. The reasons that things happened the way they did was probably because the Android phone was staying within protocol, but exhibiting different behaviors than the other Windows/Apple devices on the WLAN, and those compliant - but different - behaviors elicited a bug in the router's software that the other devices did not trip.
That's the deal with Wifi. It takes two to tango. And there's always the possibility of other crap (portable phones, microwaves, baby monitors, wireless analog cameras, fluorescent lights) spoiling the dance.
Sorry to say it, but interop problems happen all the time with WiFi.
If you want to solve them in a particular instance, you have to start digging into the details.
If you control the WiFi router in question, there are far more knobs available to turn on the router than on the phone/tablet. Upgrade your router firmware, and start turning off unnecessary behaviors on the router. If you reduce the constellation of possible behaviors on either or both devices, the likelihood of bug expression will decrease.
.
