Biz discoloring fabrics?

Hi all, I’ve been lurking (and learning) for a few months now and have run into an issue.

I have a top loader with no agitator. It’s a newer washer that senses the weight of the clothes and fills accordingly to save water (aka never fill enough to fully submerge the clothes 😒)

When I start a load of laundry, I put biz in the drum, load the clothes, and then once the cycle is starting to fill I add liquid detergent on top (diluted with the running water- this is a lesson learned from another discoloration event years ago with liquid detergent). I’m afraid to put any product on top of the clothes undiluted.

I’ve noticed 3x now that the biz powder has discolored the laundry items at the bottom of the drum. I guess it is too concentrated and doesn’t dissolve and distribute evenly? Does anyone have tips on how to avoid this? It has been a bummer to permanently discolor a couple of clothing and bedding items.

Thank you!!