I had to deactivate Justified, because after deactivating Jetpack Tiled Galleries to check if it would solve the “vertical line” problem – I couldn’t switch back to JTG while Justified was active.
Notes:
Switching to header location doesn’t fix the “vertical line” problem. Nor did deactivating JTG – which resulted in all my galleries having the “vertical line” display.
Maybe there is conflict with Thesis theme ? I’ll try to check later.