ATL is shared between SYSPLEX1 and SYSPLEX2. Each plex has its dedicated TMC. A tape defined in the TMC on SYSPLEX2 should be inserted. The INSERT request was ignored by CA 1 CBRUXENT on SYSPLEX1, as the tape does not exist in the TMC on SYSPLEX1, but it was not inserted in SYSPLEX2 and was left in the INSERT category.
No tape drive was online in SYSPLEX2.
As per IBM, it is required, that at least one tape drive must be online to process the INSERT request.