Thank you for the sample. I uploaded it into one of my accounts and fetched with Aqua Mail.
Here is what I got (attached).
If you'd like to diagnose this further:
Please enable debug logging (at the link in my signature), open such a message, do Menu -> Diag: reload (bottom item in message view menu), wait to complete, the send the log file to support / at / aqua-mail / dot com.