Since git hash 53d6b4f342140f9a807ee1ca087dbeaf0367ade7 which was merged 2019-05-22, some formats no longer work.
For one such format, the reason is clear. nillable optional elements with zero-length aren't being treated correctly.
Specifically nilValue="%ES;" and nilValueDelimiterPolicy="none"
An element that is nillable, but also minOccurs 0 maxOccurs 1 should appear in the infoset as nilled, but current behavior is it is being omitted.
Even when the element is optional, nil takes precedence over optionality.