It seems that after every restart of Magnolia, a new node is created under "sessions" in the workflow workspace.
According to ejervidalo, there should be only one session in use and the first node ("0") should be re-used instead of creating a new one.

Problem:
SystemContextSessionStore#generateSessionInfoId is doing a while loop and increasing the count of sessions thus the ID whenever its already present and this behaviour is most probably causing the problem of having a separate session on each restart.

https://git.magnolia-cms.com/projects/ENTERPRISE/repos/workflow/commits?until=refs%2Fheads%2Fbugfix%2FMGNLWORKFLOW-324