LAG LACP & Promise Sanlink2 OSX Bonding

Hello Everyone. 

I'm having some issues with 10gb LACP bonding and OSX with my XS728T. Currently, I'm using a SANLink2 Copper and two Cat6 cables to connect to the XS728T. I have set up the LAG and enabled LACP on the switch; the mac connects and all is good. However, as soon as I restart the mac I loose the bond and the switch reports the LAG as down. Going into the OSX network settings an error is shown as bond failed as the switch/other device doesn't have LACP bonding enabled. 

Now I'm sure this is an issue with OSX as my NAS (that also uses LACP) has been working solidly for about a year. Has anyone else had this problem? any help would be greatly appreciated. I can replicate the fault on OSX 10.12 & 10.13.