Why would they flex the front axle ??
Share with us this insight you have into their action...
Having said that, Triumph, along with some other makers of forks, had forks that would vary the wheelbase (more than forks do anyway), so the front wheel could ride back and forward. Certainly for racing this was not a too desirable feature, but for road use Triumph persisted with it for some decades.
Wise old riders strapped up their Triumph forks though, since if the forkspring broke there was then nothing much restraining the wheel from trying to go under the bike. Not sure from the parts page if this is still possible in this later model, but it would seem so ?