csf.conf not rotating csf.deny entires?

My idea is that you have misinterpreted the observation that an ip was not added to the cfs.deny list when you expected it to be.
If you have the cfs settings...
LF_MODSEC = 5
LF_MODSEC_PERM = 1
You may expect 5 hits from your modsec wp-login.php rule to be enough to satisfy the conditions to be added to the cfs.deny list.
That is not necessarily the case.

cfs uses the lfd to parse apache error_log lines for the line fragment "Access denied with code 40*"
If 5 lines with that fragment are present for a particular ip then it is added to the cfs.deny list.

For Modsecurity to write that line in the apace error_log either the ruleset default action must be set to log...

Code:

SecDefaultAction "phase:1,log,auditlog,pass"

Note the word log.

Or the rule in question must override the default action by including "log" in its actions.

Code:

SecRule REQUEST_FILENAME "@endsWith wp-login.php" \
        "msg:'wp-login rule is being hit',\
        id:1111111,\
        log,\
        deny"