Weekly Update (3/31/22)
Issues Missing From DCUI
Removals:
Not one, but two missing issues have turned up! Blackhawks (2011) #2 got fixed, and Suicide Squad (1987) #21 was added. 
The number of missing issues goes down to 17.
Hat tip to @Vroom for pointing this out, otherwise I wouldn’t have thought to check, at least not for a while.