Users logging on to CICS appear to be timed out by ACF2 within a few IDLE cycles, even though they are active. Recently PTF SO10542 was applied on that system.
PTF SO10542 was PE'd as a fix in error . The PTF was causing "orphaned" KTRT's. The orphaned KTRT's are happening from logons generated from a signon without password, such as with ATTACHSEC=IDENTIFY to a remote CICS region. Some of the KTRT's may have been referenced in error by the TIMEOUT function, resulting in a user incorrectly being timed out and disconnected from the CICS region even though they just became active.
Release : 16.0
Component : CA ACF2 for z/OS
Hyper PTF SO12929 resolves the problem:
Title: CICS: ACEE STORAGE LEAK; NO PW SIGNON FAILURE W/SO10542
***NOTE*** This PTF corrects an ERROR hold on CAX1G03
**** HIGH IMPACT NOTIFICATION ALERT ****
With ACF2 CICS PTF SO10542 installed signons without password
may either fail or create an orphaned SP255 ACEE.
This may result in a storage shortage in the CICS region.
Abend S653 or S878
Inheritance or preset Signon failures or eventual region abend.