I've done tpe turns before and the agent just have to tag to the final destination
Eg

Hkg-tpe-hkg-LHR

The agent accept the bag at hkg will just disregard hkg-tpe-hkg and just issue a hkg-LHR tag. The agent told me the system will not allow tags going back to origin.

So my issue is that for hkg-cmb since it stops in sIn. Will it cause problems if they tag hkg-cmb-sin???