My minecraft client crashed when I tried to use the stone cutter add on feature for the backpack.

crash-2021-10-30_11.08.19-client.txt

To Reproduce
Steps to reproduce the behavior:

1. Open backpack
2. Click on 'stone cutter' tab,
3. placed one cobblestone block in the processing section and clicked on the the slab icon
4. Client crashes

I tried to take a screen shot but my client crashed after the stone cutter tab had been open about 10 seconds

you need to update your forge version. that updated version of sophisticated backpacks has fix for new forge version specifically in that place where it crashes for you on the old one.