This makes sense! .5.101 is told to use IPFire, but the device can not be urged to use this information. I suppose the log message documents such a ‘independent’ action.
The DBL suppresses this by giving answer “not known”.
Knot-resolver does not include the list name in its log output.
To change that then the knot-resolver developers would need to change their logging source code or someone using IPFire could create a patch file for the knot-resolver code and submit it to knot-resolver as a patch submission or as a pull request.
Currently what can be done is if you find an entry that you want to investigate to find which specific blocklist was involved, you can copy the name from the line in the log and put it into the Search DBL box at the top of the IPFire_DBL page and it will show in which list the entry was blocked.