Azure topic subscription doesn't receive messages >50KB

Question

I have a simple topic with a single subscription. I can send receive messages consistently when I keep the size of the message small (50kb or less is fine).

When I try to send a message with a larger size larger than ~50kb, the message is sent successfully, but never received.

The messages are not in the dead letter queue. I've abandoned messages and after a few retries they are received from that sub-queue, but these messages don't show up there either.

The message is really simple:

[DataContract]
public class TopicMessage
{
    [DataMember]
    public DateTime SentAt { get; set; }

    [DataMember]
    public string Payload { get; set; }
}

Creating message of a certain size is here:

var topicMessage = new TopicMessage() ;
topicMessage.Payload = new string('z', sizeInKb * 1024);

Finally, after sending a 64kb message to make it fail, all the following messages will not be received.

The code for the send and receive is very "hello worldy", but if it's helpful, I can post more of it.

This question sounds very similar to my problem, but doesn't have an answer. Deleting the subscription doesn't seem like a valid solution. Receiving message from Azure Topic yields null, topic has unread messages