PHP Error showing up on backup firewall (CARP)

[Dixit]

We have a pair of SG5100 Netgate firewalls and we have them configured for CARP failover and we also have the pfBlockerNG_devel configured to sync via the XMLRPC in settings for pfBlockerNG.

Our primary firewall doesnt display any issues but out backup/failover one shows 100s of these issues after a week or so. Here is an example of one:

PHP ERROR: Type: 1, File: /etc/inc/util.inc, Line: 858, Message: Uncaught ArithmeticError: Bit shift by negative number in /etc/inc/util.inc:858
Stack trace:
#0 /usr/local/pkg/pfblockerng/pfblockerng.inc(3283): subnetv4_expand('105.27.245.230/...')
#1 /usr/local/pkg/pfblockerng/pfblockerng.inc(3579): pfb_collect_localip()
#2 /usr/local/pkg/pfblockerng/pfblockerng.inc(439): pfb_daemon_filterlog()
#3 {main}
thrown @ 2019-09-24 00:07:32