After the changes to the solder, the normal BZ solder is still obtainable on Fulgoria from scrap, but cannot be recycled and it has no use.

Thanks for the feedback!

I corrected results in scrap recycling and casting solder. The old solder can be thrown in a recycler now for a 1:1 conversion to the new solder.

The issue still persists. I looked at the recipes in the factoriopedia, red circuits are is causing the regular bz solder to be produced. It only shows on hover of the recycling recipe, but from what I can see bz solder is completely removed from menus. So, for example, on Cerys you can get red circuits from recycling scrap and then when you recyle it you get the old solder. But what I can see the ingredients are correct just the recycle recipe is wrong.

you can throw the old solder into a recycler and get new out, i will work on a better fix.

got a fix in the pipeline, will be out next release!