I have received 2 "Order Help Request" messages in the last 24 hours which open with NO TEXT in the text field. The first line of the message is displayed in the inbox and it is possible to read the entire message by hovering the cursor over the inbox text. So far I have been able to successfully respond to the messages.
I've tried opening the text from the main Inbox and Order Help Request inbox... neither one opens with the text field intact.
I have not received any "regular" conversation messages in the last 24 hours so I don't know if this issue is limited to Order Help Requests or is a problem for all messages.
So far my problem hasn't been resolved.
There are a number of threads about related issues - you might want to check out https://community.etsy.com/t5/Technical-Issues/UPDATE-Messages-appear-to-not-send-when-responding-fr...
This isn't the same issue.. the thread you attached is regarding sending messages, not receiving them..