Hazelcast embedded cache printing too many logs( Target is this node! -> [10.1.8.58]:5701","stack_trace":"<#d3566be0> j.l.IllegalArgumentException...)
The exception you get SplitBrainMergeValidationOp means that the Hazelcast cluster might have been started in the split-brain and later tries to merge into one cluster. Could you check if you follow all the Hazelcast Kubernetes recommendations?
Especially, check if you use StatefulSet (not Deployment). In the case of DNS Lookup discovery, using Deployment may cause Hazelcast to start in the split-brain mode.