Sorry if it wasn't help you. ^^
I had exactly the same logs as you in log level 10, it's why i answer. The call and the quit.
For me the real problem is the error not returned ... it's not normal.
In my issue, it was an error but it try open the file in tmp, it shouldn't try to open (obviously file not found ...), it should return the real error ><
It's why i execute manually youtube-dl with full parameters with it was called by sinusbot to see my error, and i was surprised.
Edit :
A friend has the same problem, he said to me his limit is 700, but for me the limit is in bytes not mb (see the part of error i was typed in my post)
so he have modified with the value in bytes and it works for him too.