The problem at hand has gained our attention, however the circumstances of this behaviour remain mysterious.
If you want to add anything to the problem feel free to engage in the english opsi forums. Especially we are looking for signs on how to reliably reproduce the error!
If you are in posession of a support contract with uib please contact us!
To workaround the problem using Java 7 or 9 will solve the problem.
We also had reports that restarting opsiconfd will let normal operation resume.
With kind regards