Long startup, only mails from before start

[Fjodor42]

Deploying pixelated-user-agent alongside LEAP on my provider server via puppet-pixelated...

When I restart the agent, there is a very long delay (20-30 minutes), where RAM usage grows and grows (had to go from 4 to 8 GB for the machine), and 1 core is 100% utilised, until, all of a sudden, RAM usage and CPU drops, and I can log in via my browser.

After logging in, however, I will only ever see emails that were received at, or earlier than, the time at which I restarted the agent.

How can I troubleshoot this?