Bug: Node erroring when requested for address delegations before v6.0.0 upgrade

[frangrech]

System Information
Archway Version: 7.0.0
Commit Hash: 6b7bbb5
OS & Version: Ubuntu 22

Expected behavior
When querying an archive node (or a node with blocks before the v6.0.0 update) using this endpoint /cosmos/staking/v1beta1/delegations/{delegator_address}, the node returns the correct response without erroring for all blocks.

Actual behavior
The node returns {"code":13,"message":"invalid denom: ","details":[]} when queried for a block before the v6.0.0 upgrade (block 3554499 and before).

Steps to reproduce
Perform the following curl request (endpoint retrieved from registry and confirmed to be archival - we have our own archival node and it behaves the same):

curl -X GET "https://api-archway.mzonder.com/cosmos/staking/v1beta1/delegations/archway1e6tkud3yk0h68726qnqz8l8lx3dfghtvkdsupq09jgr79xnztvese9hpsy" -H 'x-cosmos-block-height: 3554499'

Trace
Nothing in the logs.