This was a known failure/fault and Triumph actually had a recall to rectify the coupling connector. Looking at the photo, the red alloy couplings on your hoses suggest that the recall was carried out, however, the plastic fitting in the tank that they plug into are prone to fail when the plastic gets old and brittle and or the o- ring swells.
There is an aftermarket supplier for the coupler fittings. In a thread here a few years ago, 2doggs posted a link to it IIRC.
Sent from my SM-G960F using Tapatalk