Problem/Bug Sharing Items Between worlds. Multi-inv---Help still needed

Hello humans. I have tried to make 2 worlds share inventories with each other and so far, I have not been able to link the 2. I have tried giving these permissions to both worlds:

Code:

        - mvinv.bypass.world.SkyBlock
        - mvinv.bypass.world.SkyBlockShop

I have this applied in both worlds. And when I go to the other, I have my stuff from the other world but when I move my stuff around, it goes back to the stuff from that world. I have also tried disabling multi inv for that world only.

If anyone knows how to connect the 2, I will thank him very much.