VLAN don't working on RB850Gx2

RouterOS General
1

RB850Gx2 have Max L2MTU 1506 of bytes.
So one VLAN should work because the VLAN tag is 4 bytes.
I create VLAN on ethernet and I have got:
MTU: 1500
L2MTU: 1502

But the VLAN do not work with the 1500 packet size. Max packet size work is 1498.
Why?

2

Ethernet interface L2MTU has to be at least 1504 bytes to allow 1500 byte packets with VLAN tag and do not fragment them.

3

Ethernet interface L2MTU has 1506 so it should be work, but it don’t work correctly.
And I don’t know what is wrong.