This appears to be a result of a bug .."(SPL-95114) where instability in an indexing cluster can lead to distributed search groups losing the internal reference to their members. When this happens, the default target group "dmc_group_indexer" acts as if it had no members even though those are listed in distsearch.conf, and as a result your searches will not be dispatched to any remote peers unless you specify a splunk_server=* or splunk_server_group=* clause."
https://answers.splunk.com/answers/221468/search-returns-zero-results-searchlog-reports-dist.html
Cleaning up distsearch.conf with splunk restart resolved this issue
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