It seems that SAP 9.2 PL06 (and perhaps also PL05) has a bug in its DI-API causing it to deadlock at a random interval. B1UP's Recurring Invoice and Master Data Manager are affected but unknown if other areas in our other add-ons are affected.
We are working with the partner that originally reported this and SAP Support to get more clarity on what is affected and how to get around it, but we have a simple code-sample that can reproduce in any database so that is a good sign at least.
We will update this when we know more but for now, we can't recommend upgrading to SAP 9.2 PL05/06 if you are using Recurring invoices or Master Data Manager.
Update: 2017-01-11: SAP Has identified the issue and has a workaround for the issue. You need to contact SAP Support and reference incident no 1867 / 2017 to get the workaround. It is also planned to be fixed in SAP 9.2 PL07
Update: 2017-01-19: SAP now an SAP Note explaining the issue: https://launchpad.support.sap.com/#/notes/2411657
Update: 2017-02-10: It Seems SAP has released an SAP 9.2 PL06 HF1 that deals with the issue :-)