Last time, in my 50,000 foot view post, I presented an overview of the purpose, the location, and the
expected lifecycle of change pointer records.    I also briefly discussed two programs:

RBDMIDOC

–  triggers IDOC distribution for ‘unprocessed’ change pointer records, and marks
those change pointer records as ‘processed’.

RBDCPCLR

–   deletes the ‘processed’ change pointer records from the change pointer tables.

One obvious source of runaway change pointer table growth is never running the cleanup program RBDCPCLR.
Using transaction SM37 (batch jobs), you can determine if RBDCPCLR is running in a batch job, and how frequently it is running.
As shown in the screen shot below, enter RBDCPCLR in the ABAP Program Name box, enter a relevant date range,
and check the various job status boxes that you might be looking for.  I recommend setting a significantly wide date
range, as I have found situations where RBDCPCLR was running in a scheduled batch job a while ago, but for some
unknown reason is no longer currently running.

Pressing the EXECUTE button will produce a list of batch jobs containing RBDCPCLR.