When query result candidates are collected for a class that has JDO versioning enabled and the version is stored in a field of the class, an invalid column name ('VERSION') is added to MongoDB object field selection list.
This bug occurs only when the version number is stored in a field of the class using DataNucleus extension and does not occur when using a surrogate column. Because the version field belongs to the default fetch group and thus, in most cases is retrieved anyway, the problem won't manifest in a typical use case. The only symptom will be a log message of DN trying to fetch unnecessary field 'VERSION' from MongoDB.
A patch with proposed solution, duplicating the version column name selection logic from MongoDBUtils class is attached. I can provide also a testcase if it's necessary.