Running this against a SQL 2016 server, I have found numerous instances where wait_description is not null and hid is null.  I changed the following statement as follows:

original:

INSERT [#obct_locks]([hid],

[wait_description],

[dbid],

[associatedObjectId])

SELECT [blk].[hid],...

Thanks very much for the script. My only problem is that I live in a case sensitive world so I had to modify the create #TMP table to use...

Check for uncommitted transactions.