Refresh token issued before the client session started

Hi,

I’m encountering a strange behavior and I don’t know where it might come from. I’m not primarily looking for a technical explanation, but I want to know why this might happen:

During a refresh_token grant, I get the error message invalid_token and the detail message refresh token issued before the client session started. This is coming from the TokenManager.validateToken(...) method. So far, this is clear to me.
But how can this functionally happen? Might this be an error from the client implementation?

Yet, I have never encountered this error, only in one environment, this occasionally happens. And I don’t know why.
Only SSO session idle/max are configured, no deviating client session times, not globally, not in the specific client.

Has anybody any ideas about this? Any solution approaches?

Thanks
- Niko