Tahoe's Contact App is broken. macOS 26.2 exampe. Changing data values with out user input and ignoring correction attempts.

Good ideas.  Our contacts set-up (in use for years and many versions i-iPad-mac OS versions since @me.com was introduced) is as follows - all devices use calendar access (via Settings>Accounts) to a) the user's apple account and b) an admin account.  New contacts are added to the admin account for distribution to all devices via iCloud.com.

On a macOS device, I validated that both accounts contain the same errors (or Contacts' version of what it thinks is the correct data).

On your clean-up idea through the browser, as I have two copies of each contact (one in the admin account which is the master) and another one that is in a user account, I tested whether or not iCloud contacts allows me to correct the data.  It appears that it does with some misses.  Taking one of them, it looks like the icloud version accepted the data corrections for both the view and edit modes.  For the macOS  sync version, while the view mode displays the corrected data, the edit version is only partially correct for the non-name fields data (which are still grey as perhaps the suggested values).  The name field still shows the suggested bad data that was corrected in the icloud version.

Given the number of contacts we have, I don't think I'm ready to start a cleanup project just yet.  ( I have all the data backed up.

Is there any chance that Apple reviews the community logs?  I ask because I tried their feedback process.  The amount of text is so limited that the points made here are not able to be entered for Apple's review.  I've asked if there is another route available to provide more complete feedback.

Wow, that took some digging to find that post. The post's "third" Apple (ID) account is the path taken to eliminate the maintenance or need to accept additional contacts for the admin account's.

And, hey, your idea to check icloud directly helped make it not a red alert problem.

The history of this solution actually has its roots in how to share calendars after the demise of Apple's Server OS product was scuttled (please resurrect Apple) which was run on a mac mini. The mini is today where the main host for the admin account is sited. While the admin account is available on most of the devices, only on macOS can you truly log in to both the individual and admin account directly via fast user switching. I wish this was true for iOS, but Apple would need change iOS name to OS, the iphone name to phone, and ipad name to pad (weak attempt at Apple humor).

I have sent the feedback. When I have time, I will call in and go through their escalation route to provide the feedback to one of the senior techs.

John, per Zurarczurx response, suggest you post a screen shot of what you are seeing to clarify the experience you are having. The community may not get to it as quickly as you would like but we do try to support each other as our schedules allow. I was notified of your note at 20:06 my time which is my clean up the day hour, so that's why I saw it so quickly - it's 20:14 just now.

Your Genius Bar for online support is a great idea. As a stock holder, I would support that - it would be well beyond what Microsoft and Google offer from my experience. Support AI is not there yet, but doing it with humans would build a training baseline for AI to learn from.

I think I should have waited to upgrade, too, to your point.

Zurarczurx, correct that this is not the issue I posted this thread about, though John found this thread from the search, so... On the issue I am concerned about (data of record), my plan is to get escalated to a senior support advisor via phone calls when I have time a window to start that. That's how I've had success with Apple. Might take a few weeks... FishingAddict's thoughts helped push me in the right direction, i.e., testing out the Contacts app in combination with using into iCloud's Contacts app to establish what iCloud's data of record is for a baseline.