User forced to login again after several minutes

[Sven]

One of our users, who is a JSM Agent, is repeatedly being prompted to log in after an unspecified period. The user receives a message stating that the queue is outdated, after which he has to log in again.

We have thoroughly checked our settings and found no issues. Our authentication policy also seem to be working fine (idle session duration 24 h). This problem is reported by only this one user. The issue occurs across multiple browsers including Firefox, Edge, and Chrome. Interestingly, when I log in as an admin using the affected user's account, the problem does not occur.

Any ideas?

[Sven]

This is how the log looks like for this user

It is noticeable that there seem to be multiple parallel connections. This is not the case with any other user.