Upgradeable DApp (upgrade contracts in a set of connected contracts)

I understand there are many well written articles on upgradeable smart contracts, but as the title suggests, is there any known issues in upgrading one contract in a set of inter-connected upgradeable contracts? Or is there any well written example of this sort?

The complexity resides in
1). each contract is upgradeable;
2). all contracts are inter-connected.


Emmm, I think if you provide some code that show in a bare minimum will be helpful.