NullPointerException in XMLStreamDataWriter.writeNode

We're encountering sporadic weird NullPointerException in various of our tests using different client configurations with wsdls. It seems to only occur right after initialising the client, e.g. only on the first call. I suspect it's some kind of race-condition, but I've not been able to create a reproducer. I was hoping maybe someone from the project would have insight into why this could be happening by looking at the stacktraces.

The error we're hitting appears to be here:

java.lang.NullPointerException: Cannot invoke "org.w3c.dom.Node.getOwnerDocument()" because "nd" is null
	at org.apache.cxf.databinding.source.XMLStreamDataWriter.writeNode(XMLStreamDataWriter.java:160) ~[cxf-core-4.0.4.jar:4.0.4]
	at org.apache.cxf.databinding.source.XMLStreamDataWriter.write(XMLStreamDataWriter.java:101) ~[cxf-core-4.0.4.jar:4.0.4]
	at org.apache.cxf.databinding.source.XMLStreamDataWriter.write(XMLStreamDataWriter.java:67) ~[cxf-core-4.0.4.jar:4.0.4]
	at org.apache.cxf.databinding.source.XMLStreamDataWriter.write(XMLStreamDataWriter.java:55) ~[cxf-core-4.0.4.jar:4.0.4]

Update: we're using cxf-rt-transports-http-hc5.
We've had this issue on 4.0.3 and 4.0.4. We might've had it on previous versions as well, but I don't have build history going back that far.

JDK versions: Corretto 17 (17.0.8-amzn), Zulu 17 (17.0.10-zulu) ++