Found message +TN0898I IPT table is full.
I didn't find it in any MAT manual or Broadcom search. Not quite immediate to a monitor request:
10.14.36 STC24084 TN0300I MONITORING STARTED FOR PROFILE CICSAP2A BY USER B23069 FROM SERVER CAMAT
10.15.09 STC24084 +TN0898I IPT table is full
This happened in five CICS regions. What does it mean?
Release : 12.0
Component : CA MAINFRAME APPLICATION TUNER
An overflow of an IPT table used by MAT, could be caused by an internal loop addressed by PTF SO11963.
The message itself does not mean MAT is failing, on the contrary it's says that the IPT table is full (2000 entries) and MAT is doing normal housekeeping ("an informational message and start to drain,summarize and reuse the same table").