Inventory viewer usage not being logged
This plugins is not getting logged, not a clue why.
Is the logging of inventory viewer set to true in config?
    "Inventory Viewer logging (true/false)": true,

in other words yes it is.

Hmm, can't find anything wrong with the code.

Does everything else get logged?
Did you install InventoryViewer plugin?
Do you have permissions set for InventoryViewer?