Minecraft Version

1.20.1

What happened?

To preface:
This is quite likely to be an issue with Custom Portals itself - but it's possible it's Curios, so I figured it's worth opening. Custom Portals is a Fabric mod so I am using Sinytra Connector which could also be why there's problems.

Issue Summary:
Going through custom portals will make curios items temporarily stop working (most notably are ones that use keybinds like backpacks) until you reopen the Curios menu manually from your inventory. Going to another dimension through one of these portals does the same thing, but you need to Disconnect/Reconnect from the server to get all Curios items back in that case, the menu shows no equipped items otherwise. If you have too many curios slots, it seems that some items can be deleted when this happens as well, but that has been a rare occurrence.

Reproduction Steps:

1. Install Curios API
2. Install something that uses Curios API (Useful backpacks is an easy example)
3. Install Sinytra Connector
4. Install Custom Portals
5. Create and Enter a custom portal
6. Curios items (such as backpack keybind) will no longer work until menu is reopened.

Custom portals link

Relevant Log Outputs

No response

Since this is a cross-loader issue using Sinytra Connector, it's most likely an issue with Connector causing some sort of desync when using portals. While it may be caused by Custom Portals specifically, there's a possibility they may not be able to resolve it either if it is a problem with Connector itself and how it handles the cross-loader logic in this case. I would probably try to report it to Connector since they would have the most knowledge about this situation.