Bit of a long shot - I have the narrow splined sprocket carrier on my Rohloff folder and occasionally clip the chainstay with my heel and the extra couple of mm with the standard version might help (Well the plan is to combine with pedal and chainring washers to get 5mm)
Part numbers
8540S to swap
8540 required
If there's no interest in swapping, this will be for sale and I'll buy new unless anyone has one for sale.