I ran across the same error. I believe it is related to an incomplete (timed out) bundle push.
Error
cluster-master : (/opt/splunk/var/log/splunk)
splunk $ grep -i bundle splunkd.log
04-27-2018 16:05:30.747 +0000 WARN PeriodicReapingTimeout - Spent 18915ms reaping replicated bundles in $SPLUNK_HOME/var/run/searchpeers
04-27-2018 19:03:23.439 +0000 WARN PeriodicReapingTimeout - Spent 11606ms reaping replicated bundles in $SPLUNK_HOME/var/run/searchpeers
04-27-2018 19:03:56.354 +0000 WARN PeriodicReapingTimeout - Spent 14195ms reaping replicated bundles in $SPLUNK_HOME/var/run/searchpeers
Doing the following (on the Cluster Master) resolved it:
Restart CM
splunk enable maintenance-mode
(Optional: splunk show maintenance-mode)
splunk restart
splunk disable maintenance-mode
Rolling Restart & Confirm
splunk rolling-restart cluster-peers
Wait 30 mins. (Time depends on the amount of indexers - this environment has 18)
splunk show cluster-bundle-status
Bundle Push
If the peers are not all displaying the same active bundle, do a bundle push.
splunk apply cluster-bundle
(Wait 30 mins)
splunk show cluster-bundle-status
... View more