The command ASID CICSREG1 is issued but SYSVIEW switches it back to the last used ASID.
SYSVIEW 16.0 & 17.0 - z/OS supported releases -
It depends if CICSREG1 is a monitored CICS region and if it is being monitored by SYSVIEW
• If the target address space has never been set to a monitored CICS address space within the session, the target value will be set based on what CICSTGTDEF set to in your profile. Otherwise the target will be set to the last used CICS address space.
• If CICSREG1 is not being monitored and CICSTGTDEF is set to FIRST (which is the default value in the DEFAULT profile) and that CICSAS1 appears first in the list of monitored CICS address spaces, so the auto-switch to that region occurs when entering CTRANS.