Unable to select VLAN interface for a PPPoE-Client

Hi,
I’m running 6.48.2 and I have this problem creating a PPPoE over VLAN.

I create the VLAN over the ETH1 interface, and all is ok.
Then I try to create a PPPoE over the VLAN, but the GUI allows to select only other interfaces, not the VLAN just created.

Using the CLI I was able to create:

/interface vlan add interface=ether1 name=ISP vlan-id=875
/interface pppoe-client add add-default-route=yes disabled=no interface=ISP keepalive-timeout=disabled name=FTTH password=test user=test

but the GUI still reports the “bridge” as active interface, and if I save it it will change the value.

Is this a bug? any idea?
thanks