Decrypting multiple WPA connections

I've been fiddling around with wireshark capturing packets from my (WPA2 protected) wlan.

I got it to decrypt traffic when it see the four handshakes from a device, but it if another device authenticates, it wont decrypt traffic from that device.

So it goes like this: I have set up the passphrase in preferences, nic is monitor mode.

• Start capturing.
• Restart my iphone's wifi
• EAPOL packets apear and subsequent traffic from my iphone is decrypted
• Restart my (other) laptop's wifi
• EAPOL packets appear but the traffic from this device doesn't get encrypted

If i do this the other way around: stop capturing, restart capturing, restart my laptop's wifi and then my iphone's. It only sees decrypted traffic from my laptop.

How can i fix this?