Why this kind of case is misleading
The customer symptom here was a mixture of charging trouble and boot-loop style behaviour. That combination can send diagnosis down the wrong path if the repair logic is too narrow. The recorded lesson on this case was especially useful: it initially looked like a CD321 or EEPROM issue. There was even partial behavioural improvement after an EEPROM rewrite, which made the wrong theory feel more believable for a while.
What the real root cause was
The final root-cause note was: water-damaged battery connector causing unstable charging and power behaviour. The measurement note also backed that up: PD negotiation unstable, partial improvement after EEPROM rewrite. In other words, the case only made full sense when the corrosion-driven instability was identified.
What fixed it
The recorded fix was cleaned and repaired water-damaged battery connector. The final case status was Fixed. That is exactly why water-damage diagnosis has to stay disciplined. Sometimes the symptom imitates a more complex subsystem issue, but the real cause is corrosion disrupting power stability.