Problem moving seamlessly between WLANS

unknown

We have 2 wlans .. both similar setups... one using Hotspot (WISPr) to auth through captive portal.. the other wpa-mixed passphrase.

Problem is we have staff who need access to both, depending on their physical location on site. When accessing the WLAN with passphrase, the device remembers and is authed immediately, however WLAN with hotspot seems to de-auth the moment device moves over to the other WLAN, therefore requiring re-auth when returning. The disconnect/de-auth does not happen if device leaves site and returns (grace period working fine), only if device moves to other SSID and returns.