OK so looking at that log it seems to me that their LMS is removing the quotes from the 'suspend_data', which makes it invalid.
According to those logs, the data being returned to the course from the LMS is:
But it should be like this:
Try putting either of those into a JSON validator and you'll see that the first is full of errors but the second is error-free.
You should go back to the people who control the LMS and explain this to them. They should not be changing the suspend_data format - JSON is perfectly valid.
Hope this helps.