Losing patterns from projects

I’ve started using the project feature recently, and noticed to my dismay that I’ve lost patterns from a couple of projects.

Say I have a project in slot 2 with some kits and patterns. I save the kits regularly, and save the project every now and then. Then I create a new project in slot 3 and start working in that project. Now when I go back to project 2 the kits are still there, but all the patterns are gone.

This has happened a couple of times already, but I haven’t been able to recreate the bug/problem now that I’m aware of it.

Is it necessary to explicitly save the patterns, or should the project save function take care of that?