Traffic dropped inter vlan interface same "physical" interface Forrtigate VM

Hi,

I am experiencing traffic loss from the interfaces (vlan subinterfaces) .

For example I have Interface vlan3333 and vlan 3334 in the same parent interface (port8) in Fortigate VM. As soon as traffic flows from vlan3333 to vlan3334 I am encountering packet loss. The physical interface (port8) also drops packets, it's like the whole interface is affected by this.

I've changed the vlans, I've chenged the parrent interface,  I even downgraded from 5.4.1 to 5.2.2.

What is happening? I've never encountered this with a physical box