No, it's the way that StreetComplete works (or doesn't, perhaps, in this scenario) – I've noticed myself that when it asks whether there is a height limit under a bridge, the location marker is somewhere along the way that extends under the bridge – this note is located around the middle of the segment of A26 way that goes under the railway bridge to the south.

Anyway, I know from passing here that there is no maxheight signage on the railway bridge, so will tag as maxheight:signed=no