I'm failing ALB health-checks on one random instance, but never both, what could be the issue?

[MP32]

For some reason when I'm deploying Jira to 2 EC2 instances, it's always one instance that fails the ALB health-check and never the other. Yesterday my instance in us-east-1a passed while my instance in us-east-1b failed. Today, after shutting down Jira on both instances and starting them back up again, the roles are now reversed- my instance in us-east-1b passed the health-check and my instance in 1a didn't. I have my health-check path set to /status which I found in an Atlassian document, but is there a Jira configuration issue causing this? Can it only run on one instance? I'm also using a trial license, can that cause Jira to only work correctly on one instance at a time? 

When I run  wget http://localhost:8080/status on the healthy instance it gets status code 200, but on the unhealthy instance it gets 500. Both instances are from an auto-scaling group so they both use the same userdata script/configuration.

Literally my instance in 1a was healthy and my instance in 1b was unhealthy, then I stopped/started Jira on both instances and now 1b is healthy and 1a isn't. It seems like something weird on Jira's end that could be causing this?