How to see UPnP devices of other Vera edge? How else can you combine two Vera edges?
You can bridge the two controllers, or use a third-party ‘master’, such as OpenHAB or openLuup, running on a separate machine.
А по инструкции , добавление upnp device?
For instructions on bridging, see here:
https://support.getvera.com/customer/en/portal/articles/2949608-q-how-can-i-bridge-two-controllers-
“Does not see the second Vera” …
… may be a wrong setting on that Vera, but your best bet now is to reach out to Vera support.