php - Magento Multi-store parked domain - weird domain url jump in admin panel and front end -

i running magento multi-store (store views) parked domain different countries (e.g. .com.au, .co.nz)

when navigating around in admin panel of .com.au (which main store view), domain changed .co.nz disabled me perform actions changing order status.

also while customers navigating in .com.au site, bring them .co.nz shopping cart after clicking "add cart".

does have solution or idea might have went wrong? please help.