That doesn’t make any sense. There’s nothing in the HTTP/1.1 spec about a limit on the number of chunks in a chunk-coded body. This sounds more like some implementation limit in the proxy’s parser, and they’re making an excuse that it’s invalid input.
I don’t think any of us on the team know the details of how the HTTP library chunk-encodes bodies. You’d probably need to dig into the implementation of that library. (Sorry I can’t be more detailed, but I don’t work on our Java implementation.)
It is possible that we could improve the way we send this HTTP body such that it wouldn’t need to be chunk-encoded at all; generally if you can specify the size of the data up front, chunk encoding isn’t necessary. Again, I don’t know the details here. @hideki is the expert on the Java implementation.
But in the short term, I think your best option is to work around your proxy’s problem. Can you turn off the setting/policy that triggers this error?