As typical when relying on Wiki sources, quoting what some authors think may happaned or not, this is wrong.
First of all, SMS LÜTZOW most likely received a tropedohit earlier, hitting the foreship. This has been claimed by HMS FALMOUTH 18.25 discharging torpedoes from a distance of only 5500 yard and has been verified by survivors from LÜTZOW in german sources. Campbell disregards this hit, but he fails to give a reasoning for this revision, and in light of aviable primary sources from both sides, it´s very unlikely that it didn´t happen.
Second of all, LÜTZOW was scuttled with help of two further torpedoes, one passing under the stern, the nex hitting amidships.
By 02:45 Lützow was submerged up to her bridge.
Not the birdge. This is an exaggeration. In german sources about nearly the top of B-barbette is mentioned in this context, not the bridge, that´s what other subsequent authours made out of it. Anyway, this is not surprising, given the fact that Captn. Harder already ordered the crew to abandon the ship and hence, end the state of combat watertightness ("Gefechtsverschlußzustand" in german sources) of the internal spaces, thus water could spread at will unhindered by watertight doors and manholes anytime after 02.20 (=01.20 german time).
At 02.30, f.e. (UK time = 01.30 german time), when the last DC controll reading has been entered in the log, and after the combat tighteness was already lifted for ten minutes, the draught forward was +8.5m with an estimated 8,500t (metr.) water in the ship. At this point the forecastle was just slipping under the water with both turrets clear of the waterline. Wateringress then spread rapidly across the ship in the 15 minutes to 02.45.
After Jutland, the case of SMS LÜTZOW was discussed in the Marineamt because the complete damage report logs have been safed by the crew. It was established that the ship had enough buoyancy and stability for approximately two days, providing the wateringress could be stabilized but it couldn´t steer with help of the screws and would require to be towed by other ships sternwise.
The prime reaon for the loss was claimed to be wrong handling of the ship, that is an unwisely high speed which strained the fore transverse bulkheads and triggered them to fail at about midnight in an ill fared attempt to flee the area of fighting.