encapsulation

hi,

any idea why this error occurs?

@Template-vQFX-Light# show | compare 
[edit interfaces]
+   ae10 {
+       flexible-vlan-tagging;
+       encapsulation ethernet-bridge;
+       aggregated-ether-options {
+           lacp {
+               active;
+           }
+       }
+   }

{master:0}[edit]
jcluser@Template-vQFX-Light# commit 
[edit interfaces]
  'ae10'
    ethernet encapsulation not allowed on tagged interfaces
error: configuration check-out failed

{master:0}[edit]
jcluser@Template-vQFX-Light#