I have used Superior and their prewound bobbins in the Mono and was very satisfied.
No problems.

That same thing is happening at my house but with a table topper. I went with the monofilament in the top and 'regular' thread in the bobbin. My sewing machine manual said to tighten the tension to #7 (gulp) and turn the bobbin screw counterclockwise 1/4 turn (double gulp). It's working fine! So check out your manual. If you decide to go that way, it may have something about using monofilament.

Edited to add: This particular piece is totally tropical colors and the neutrals just wouldn't have looked good. Besides, it's always good to try new techniques!

On my last quilt I used "invisible" thread in both top and bobbin to FMQ around each poppy in each block. I think it turned out well. I had to go slowly 'cause I'm just not that good!

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I try to match my colors. but I've also used a light grey that seemed to just blend in after it was done.
I've sent out a quilt to be quilted and she used green on the green and a gray on everything else.

I haven't used monofilament thread in my bobbin, however, several years ago, I took a class with the owner of Heartbeat Quilts in Hyannis, MA, however, I can't remember her name right now (Sr. Moment or brain cramp - take your pick); but she said that she has used the monofilament thread in the bobbin without any problems at all. She also said that some machines might not like having it in the bobbin as well as the top. That's probably not much help, but I thought I would put my 2 cents worth in, but the quilt teacher is well known, I just cannot remember her name. I'm getting older and apparently so is my memory, so old it breaks down.