Mempool additional config

I’m trying to set a mempool.space backend configuration setting, particularly, I added MEMPOOL_MAX_BLOCKS_BULK_QUERY in umbrel/app-data/mempool/docker-compose.yml according to this but after restarting the service, hitting the endpoint returns this:

curl -sSL "http://umbrel.local:3006/api/v1/blocks-bulk/100/109"
Cannot read properties of null (reading '0')%

Any thoughts how to fix this? I’m probably missing something really obvious.