Due to advanced age, the metallurgy of the ship's outer hull has "changed", due to continuous exposure to hard X-rays, cosmic rays, hot neutrons, and other cosmic phenomena, resulting in radically lower structural integrity than design spec. (and subsequently high ambient radioactivity)
To combat this, most of the voids in the outer hull's infrastructure have been pumped full of an exotic shock/stress sensitive semi-fluid metal alloy leveraging microcrystals of metallic hydrogen suspended in a gallium-mercury based suspension, which is actually quite toxic. It hardens when placed under pressure (such as when being forced through a hole or crack from internal pressure differences between the ship and the vacuum of space outside), and has been an effective stop-gap countermeasure to having the ship actually get the outer-skin overhaul it has needed for the past 2 centuries, but has never actually gotten. (mostly due to the extreme costs of properly disposing of that much irradiated durasteel)
As such, the ship leaves a trail of small metal chips, and other debris as it travels through space (due to weakened outer hull substrate flexing from uneven heating when it enters a star system, and bits of the reinforcement material getting squirted out under turning and braking maneuvers), making hyperdrive exits "interesting." (as in, unintended kinetic missiles "interesting", as well as "ship's mass is difficult to properly model for hyperdrive exit computations" interesting.)