WSDL.exe problem when using sharetypes on endpoints with different access restrictions

I am trying to generate client proxies for 2 endpoints using wsdl thus:
wsdl /out:Proxies.cs /shareTypes https://my.com/longpath/endpoint1.asmx https://my.com/longpath/subdir/endpoint2.asmx

The important thing I'm trying to achieve is shared types as these 2 endpoints expose some of the same types within the web application.

This works fine with anonymous access allowed to both endpoints. However, when basic authentication is enforced on /subdir I then have to add /username and /password options to the command line to avoid an accessibility error.
I then get the following error:
WSDL: error WSDL1: Item has already been added. Key in dictionary: '[45]:https://my.com/longpa:Negotiate'  Key being added: '[45]:https://my.com/longpa:Negotiate'

ASSERTIONS:
 - There are no object/types or any other references to "Negotiate" in either endpoint wsdl so I belive this to be something internal to the workings of wsdl.exe
 - wsdl.exe works for each endpoint individually, including the anonymous endpoint1 even specifying the unnecessary username/password
/ASSERTIONS

I think this is probably a bug with wsdl unless anyone tells me otherwise.

Does anyone know of another way to achieve the same effect as sharetypes option but perhaps in 2 batches - 1 for each endpoint so I can get this working?

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