[ICS07] Incorrect ConsensusState storage for headers with heights lower than ClientState height

[Farhad-Shabani]

Bug Summary

Reported by @vmarkushin

When a header with a height lower than the current client height is submitted for the first time, we store the consensus state at the height of the current client state instead of the provided header height. This action overwrites the existing consensus state for the current height. Since the header is from the past, a ConsensusState with an older root is installed at that path. This disrupts commitment proof verification, as the provided proof will be for a different state root than the one we actually stored.

Details

• [H] Installed headers
• (H) Unseen headers

---- [5] ---- [7] -- (8) ---- [10] -------------- (20)

Scenario: Submit a header with height 8 and the trusted height of 7

Version

=< v0.50.0