> I just don't see what might be causing this ACTIVATE/DEACTIVATE activity to occur on these 3 DB's.
Default behaviour is for database to be activated (i.e. create bufferpools, allocate shared memory, etc...) upon first connection. Once the last connect is disconnected, DB2 automatically deactivates the database.
To avoid activation/deactivation use:
db2 "activate db <db name>"
The tradeoff is more system resources are used regardless if there are applications connected to the system, but first connection from application will be quicker.
Check to see if you have any database monitoring applications that automatically connect to the database every xxx days/hours, etc... to collect statistics. Another alternative is to enable something like Event Monitor (https://www.ibm.com/support/knowledgecenter/en/SSEPGG_10.5.0/com.ibm.db2.luw.admin.mon.doc/doc/r0005993.html
) to gather info on the applications connected to the database.