Problem with 4x HP E3800 24g-2xg Switch and MSTP

[GraKa]

Hi fellowers,

I got a very mysterious problem.

I attached a file that shows the topology of the network.

I configured MSTP on every Switch. I have 4x HP E3800 24g-2xg Switch.

When all the links are cabled and connected to the 10GbE Ports the STP works just fine. Every Port except one is in forwarding state and one port is in blocking state (e.g. Port 25 on Switch4).

HOWEVER! When I unplug the cable from (Port 25 Switch2), the connection between (Port25 Switch3) and (Port25 Switch4) should change to forwarding state.

But this DOESN'T happen. The previous port that was in blocking state (Port 25 on Switch4) still is in blocking state and I absolute don't know why.

The funny thing is: When I cable the same topology with all 1GbE Ports then everything is working fine and the blocking ports are also changing to forwarding state.

I only have this problem on the 10GbE links.

Running-config of Switch1 (it's besides the OOBM ip address and the vlan1 ip address the same config on every switch):

hostname "OF459-0"
module 1 type j9585x
telnet-server listen oobm
web-management listen oobm
ip default-gateway 10.40.51.1
snmp-server community "public" unrestricted
snmp-server host 10.40.51.130 community "fhs" oobm
oobm
   ip address 10.40.51.131 255.255.255.0
   exit
vlan 1
   name "DEFAULT_VLAN"
   untagged 1-26
   ip address 10.40.51.31 255.255.255.0
   exit
spanning-tree
no autorun
no dhcp config-file-update
no dhcp image-file-update

This is the output of "show spanning-tree" on Switch1:

 Multiple Spanning Tree (MST) Information

  STP Enabled   : Yes
  Force Version : MSTP-operation
  IST Mapped VLANs : 1-4094
  Switch MAC Address : 10604b-390000
  Switch Priority    : 32768
  Max Age  : 20
  Max Hops : 20
  Forward Delay : 15

  Topology Change Count  : 4
  Time Since Last Change : 10 hours

  CST Root MAC Address : 009c02-d86940
  CST Root Priority    : 32768
  CST Root Path Cost   : 2000
  CST Root Port        : 25

  IST Regional Root MAC Address : 10604b-390000
  IST Regional Root Priority    : 32768
  IST Regional Root Path Cost   : 0
  IST Remaining Hops            : 20

  Root Guard Ports     :
  Loop Guard Ports     :
  TCN Guard Ports      :
  BPDU Protected Ports :
  BPDU Filtered Ports  :
  PVST Protected Ports :
  PVST Filtered Ports  :

                   |           Prio              | Designated    Hello
  Port   Type      | Cost      rity State        | Bridge        Time PtP Edge
  ------ --------- + --------- ---- ------------ + ------------- ---- --- ----
  1      100/1000T | Auto      128  Disabled     |
  2      100/1000T | Auto      128  Disabled     |
  3      100/1000T | Auto      128  Disabled     |
  4      100/1000T | Auto      128  Disabled     |
  5      100/1000T | Auto      128  Disabled     |
  6      100/1000T | Auto      128  Disabled     |
  7      100/1000T | Auto      128  Disabled     |
  8      100/1000T | Auto      128  Disabled     |
  9      100/1000T | Auto      128  Disabled     |
  10     100/1000T | Auto      128  Disabled     |
  11     100/1000T | Auto      128  Disabled     |
  12     100/1000T | Auto      128  Disabled     |
  13     100/1000T | Auto      128  Disabled     |
  14     100/1000T | Auto      128  Disabled     |
  15     100/1000T | Auto      128  Disabled     |
  16     100/1000T | Auto      128  Disabled     |
  17     100/1000T | Auto      128  Disabled     |
  18     100/1000T | Auto      128  Disabled     |
  19     100/1000T | Auto      128  Disabled     |
  20     100/1000T | Auto      128  Disabled     |
  21     100/1000T | Auto      128  Disabled     |
  22     100/1000T | Auto      128  Disabled     |
  23     100/1000T | Auto      128  Disabled     |
  24     100/1000T | Auto      128  Disabled     |
  25     10GbE-T   | 2000      128  Forwarding   | 009c02-d86940 2    Yes No
  26     10GbE-T   | 2000      128  Forwarding   | 10604b-390000 2    Yes No

I'm pretty frustrated because I searched like a LOT on the internet and couldn't find the solution yet.

Thanks very much in advance.

Best regards,

Stefan.