@Erik_Botta, what is the compaction setting for index? It is recommended to use “circular write mode” rather than “append-only write”. You can check under UI->Settings->Auto-compaction.
Also, for HA purpose, it is always advisable to have 2 index service nodes with an equivalent index on second node(system managed replica index in EE edition). In the event of failure of one index node, this would ensure no downtime.