De'Longhi Magnifica Plus (ECAM322.70.SB) suddenly brews much hotter than the setting, and a full descale didn't fix it
My Magnifica Plus ECAM322.70.SB has started dispensing noticeably hotter coffee than it used to. The brew temperature is set to the low end and I never changed it. I'd like a sanity check on my thinking before I pay for service.
What I've already done, so please don't just say "descale it":
\* Descaled with genuine De'Longhi EcoDecalk, full cycle, completed properly. Still running hot after 8 to 10 brews since.
\* Water hardness is on the hardest setting, so the machine has been prompting and descaling aggressively.
\* The problem showed up right after the machine got used for about 4 to 5 days while it was already asking for a descale (I was away and someone kept brewing). Descaling twice, afterwards did not fix it.
\* Only prior repair was a warranty job a few months ago: they cleared a clog at the hot water / milk spout and replaced the entire 3.5" touch display unit. It ran perfectly for months after that.
My reasoning: as I understand it, a scaled-up machine usually brews cooler, not hotter, because scale slows heat transfer into the water. The one way scale makes coffee hotter is by restricting flow, so the water sits longer against the hot block. My pour speed and cup volume look normal. So I'm leaning toward the NTC temperature sensor reading low, or the main board not cutting the heater at the target temp. A cosmetic display swap shouldn't touch heater control, so I doubt the earlier repair caused it.
Questions:
\* Has anyone had the NTC temperature sensor drift low on an ECAM322 (or similar) and cause overheating? Is it a DIY-accessible part or a full service job to reach it?
\* Any known control board or firmware quirks on this series that affect brew temperature?
\* Roughly what should the hot water tap read on this model? I'm going to measure it so I have an actual number in degrees C.
Thanks in advance.