ScriptObjectMirror does not have a no-arg default constructor

Hi,
I have recently upgraded from Camunda from version 7.8 > 7.9 > 7.10 > 7.11 and then finally 7.12. Everything went fine up until version 7.12. When I try to kick off an existing process flow I get the following error:

**The process could not be started.** **:** Cannot instantiate process definition xxx:71:33923e86-0b76-11ea-864a : Cannot serialize object in variable 'yyyy': SPIN/DOM-XML-01030 Cannot create context

Having a look at the logs it seems to be because of the following:

jdk.nashorn.api.scripting.ScriptObjectMirror does not have a no-arg default constructor.

The variable in question yyyy is created in a javascript scriptTask as follows:
def yyyy = []

I beleive this could be because of the following change: https://docs.camunda.org/manual/latest/update/minor/711-to-712/#camunda-commons-typed-values-migration

We are using Java 8 and I have tried playing around with the bpm property javaSerializationFormatEnabled using true or false does not have an effect.

Have anyone else perhaps seen this occur after upgrading to 7.12 or know how to resolve this?

full-stack.log (18.2 KB)