Session: Error while trying to free lock for ci_session:guid.lock (3.0.6)

Recently moved to a load balanced environment on AWS, ElasticBeanstalk nodes and a Redis Elasticache server for sessions (no sticky sessions). This message appears in the logs very frequently. Previously the app used file based sessions since it was a single server. It doesn't appear to break anything but I'm concerned there's an issue somewhere I'm not familiar with.

Any idea what can cause this and how to fix it?

Still haven't been able to figure out what is causing this. We've added session_write_close( ); calls on all the long running and heavily concurrent AJAX requests which helped performance but hasn't removed the error.

We plan on using Redis for other things and I could probably fix the error by changing to database sessions or using sticky file sessions but I'd rather fix it then work around it.

I get the same error. It's not much of a problem though. Did you figure out what was causing it?

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