Hallo there are some new bugs discovered after updating to Cubase 6.5.5 at the moment i took this screenshot for you. The channels moved in the arrangement does not move in the mixer too 
Look down in the mixer the channel numbers on grey is 3-4-5-6-12-7-8-9 etc in the arrangement is 8-9-10-11-12 as should be. Some one have this on Mac?
Not a new bug, this has been around since for SX3.
When adding, removing and reordering tracks on the arrange page, the channel order in the mixer can become different to the channel order in the arrange window.
The workaround is to close and reopen the mixer (hit F3 twice)
Hope that helps.
haaaa ok thanks a lot, i didnt notice that before in 6.5.4, it’s not a big issue but still there 