Just adding an update for closure on this thread...
In the end, the problem was corruption of the TLS handshake caused by a default buffer size in Microchip's TCP/IP library being too small. I haven't completely studied the cause yet, but it appears that traffic received via a HughesNet link uses a larger than typical MTU setting or something along those lines. Simply resizing that buffer made the problem disappear.
Good morning Patrick,
Thanks so much for updating us here in your thread, sounds good. I'm glad you were able to figure things out with our engineers! If you ever need anything else, please don't hesitate to reach out again!