MSTP Spanning tree instance issues

[Dzendrow]

Afternoon All,

Just wondering if someone can provide some feedback on the below issue

We have a two site setup each with two 5412r core switching / two 1Gbps links

One link is used for site to site connectivity / server / application

The other we want to used only for a specific replication link

So we created a new replication Vlan / new STP instance on either core switch

As soon as we connect the link STP still blocks it even though the replication Vlan is the only one permitted

I’ve checked logs on A / B end they show the below

 STP AM1: MSTI 2 starved for an MSTI Msg Rx on port