Acrolinx opens a lot of checking sessions for a single Sidebar Integration. For Classic Integrations, Acrolinx usually showed 1 open session per user per integration.
5.3, 5.4, 5.5, 5.6, 2018.10, 2018.11
Sidebar Integrations don't close checking sessions. Instead, the checking sessions will collect on the platform and are visible in the Checking Sessions page of the Dashboard.
After the sessions expire, the sessions disappear from the list.