In tiered/tiered_handle.c there are two functions for cleaning up and closing a tiered dhandle: wt_tiered_close, wt_tiered_discard.

In wt_tiered_close there are no verbose messages. In wt_tiered_discard there is the following WT_VERB_TIERED verbose debug message:

__wt_verbose(session, WT_VERB_TIERED, "%s", "TIERED_CLOSE: called");

There are two things to fix here.

1. Fix the above verbose message to indicate it is the discard path.
2. Copy/add that message to the close path.