Jens,
We’ve found a wayward Emmet key-binding that conflicts with the forward/backward history bindings, though the conflict appears to be Mac specific. We will remove this binding for the next release, but wanted to know you could manually remove this binding from the Keys preference page, in case you hadn’t done so already.
To remove the binding, open Preferences and go to General > Keys. In the filter area, type “Decrement number by 1”, select it and use the “Unbind command” button to remove the conflicting binding.
Hope this helps, and again, thank you for the report.