@ewan000 Trellis Layout with Real-Time Search works fine for me.
Could you share more details about your dashboard? Which Splunk version are you using? What is search query, which trellis visualization and also how much data, time window are you looking at? Simple XML code snippet and sample data would help us assist you better. Please mock/anonymize any sensitive information before posting the same on Splunk Answers.
Also, instead of real-time search can you try relative-time search with a search refresh for specific time interval like 1 min or 5 min?
<refresh>5m</refresh>
<refreshType>delay</refreshType>
If you feel this is a bug in Trellis behavior with real-time search you should reach out to Splunk Support Team with your Splunk entitlement and raise a case for the same. Also add a BUG tag to this question.
... View more