it's not hard to encode DER correctly but it takes a little effort that people don't bother to put in.
You're right, it was not hard at all to encode it correctly once I got all the facts right. Been using this "own encoder" for a while now and had no other issues whatsoever.
I encountered some other weird situation in the meantime if you want to take a look --
https://bitcointalk.org/index.php?topic=5060723Regards