Unknown layer is visible

So i have this comp with no layer visible (see left down corner) though a solid I used with a vignette effect can be permanent seen. And even with "Toggle transperency grid" set to on, the strange Layer can be seen. Does anynone know this problem? (Specs: Windows 10, AMD Ryzen 9 5900X, 32 GB RAM, AE Version: 22.0.1 (Build 2))
