Strange MSTP behavior

Hi all,

Let's focus on the following topology:

Let's suppose to consider VLAN46 which is defined in all the switches in the LAN.

VLAN46 is in MST Instance 4 (MSTI 4) in Region123 and in Instance 2 (MSTI 2) in Region456.

Let's configure a SVI on SW1 in VLAN46

SW1(config)# interface vlan 46

Let's do the same on SW6:

SW1(config)# interface vlan 46

Now, since the VLAN - Instance mapping is different I would expect that ping does not work.

However, ping does works!

It may depend on the fact that MST Instance are only LOCALLY significant?

Thanks