The behavior you report is expected, since Intel software and drivers only support a single adapter installed on one computer, as noted in the following advisory:
Frequently Asked Questions about Intel® Wireless Adapters
It is worth to mention that Linux Driver development and support is done in the open-source Linux community, so some features may vary between OS's.
We would like to inform that support for system manufacturers and embeded designs should be engaged through your Sales representative or Authorized Intel® Technology Provider.
Also, keep in mind that the installation or use of Intel® Wireless Adapters is subject to regulations and approvals depending on the countries they are used:
Regulatory Information Regarding Hardware Installation or Upgrade
Let us know in case you require have any further questions.
Thanks for the prompt reply. Your answer came somewhat as a surprise, so what are you saying is that driver is written such a way that allows only a single card per system, for both WiFi and BT parts? This sounds very odd. Is it purely software issue or hardware limitation? Was it explicitly written like this? What is a rationale behind? I don't see how company can limit only single network card installation on PCIe bus - I am just trying to find a logic here. Is it applicable to any Intel cards, like 7260, 7265 etc. or it is specific to 8260? We definitely can approach you through Avnet, but we need to know if this is a dead end or there is a hope to have multiple cards under Windows 10.
BTW - is it applicable to Windows 10 only or the same behavior is expected under any Windows flavor?
The limitation of one device per computer is present with any adapter and Intel® PROSet/Wireless Software and Drivers version. This is valid accross the different versions of Windows*.
We would like to remind you that Intel® Customer Support does not provide embedded design support, therefore, the rest of the information you requested is out of our scope.
We advise you to check with your distributor and engage our account engineering team; they will be able to address any Embedded design inquiries you may have.
Before replying to our customer we need to understand the following:
1) Is it software or hardware problem?
2) Was your driver explicitly written to handle a single card only?
3) Can you driver be modified to handle multiple cards in a system?
4) Is single card concept applicable to ANY Intel wireless card?
5) Is single card concept applicable to Windows 10 only or any Windows platform?
6) Is it ANY way to have multiple Intel radio cards under Windows? Is it completely dead end or there is a hope?
ALFTEL Systems Ltd.
As much as we would like to provide you assistance regarding your questions the answers to your questions is beyond our scope of support. Since we don't handle embedded design. Please contact your distributor in order so they can contact a field application engineer for additional support.