This is not possible on my Stromer. It wobbles like crazy. I have an ST1x, with 500 kilometres, only a month old. Is this normal for a high end electric bike?
I had the exact same issue and tightening the headset didn't work. It's because there weren't enough spacers and the compression plug didn't have enough space to pull down. Added a thin 5mm spacer and problem solved, no more "clunk" or loose headset. Next ride I'll try no hands again....