Blending filament is EVIL!!!
I used to do a lot of cross stitch, and hated it so much that I left it out wherever I didn't think it would make much difference to the finished piece. It was always getting tangled or breaking even when the threads it was paired with were behaving nicely. I tried silicone and all sorts of "thread conditioner" on it and it still wouldn't behave. I will never touch the stuff again!