I use Spacemacs started learning git so I added the git layer and amazing things were enabled 😄 . Cutting it short, quiting a magit status buffer transient keybinding state makes frame have this:

There's a fake modeline on the left that came as a result of quitting a magit transient state. I don't get the issue when my dotspacemacs-mode-line-theme is set to doom. However, I love spaceline 🙃