Where does this SSH Exception originate?

Question

I'm using the ssh.net client to connect to a sftp server that identifies itself as maverick_20, which appears to be the the closed-source offering from Sshtools. When I attempt to read bytes out of a file in stream mode, I have a general exception that bubbles up containing the string 'read from 13 for 32755 from 32772 not supported', which I believe is being returned to me from the server. That message is meaningless to me, but the server certainly allows me to seek() to different positions in the file without issue.

Googling the phrase suspiciously returns a list of ssh error codes on the WinSCP site, though that phrase does not occur in the page. As the source code for the NG product is not available, I can't investigate the issue that way.

Is the Maverick server broken in some way? I can't imagine what sort conditions would allow seek and complete file reads, but fail in this specific way.