Using classic Outlook for Windows in business environments
Hi @Vivian thank you for the follow up and the tests to try and reproduce this.
In my case i'm only looking to see if I can see all the contact data in the classic outlook desktop app which is also where I originally authored / added it all. I have never edit these contacts in outlook.com web app or new outlook store app although I have tried viewing them from those apps to see if I get a different result.
I just tried your test in classic outlook desktop app if a ctrl+a > ctrl+c while having cursor in three different affected classic outlook desktop app contact's Notes field. Followed by a ctrl+v while having the cursor in a new notepad app document to see if the content is there and just hidden but displays when notepad strips off special characters that would be hiding it. No luck only see what I see in the classic outlook desktop app contact Notes view.
What I'm gathering from other posts is that one or all of the outlook options [ web app, desktop app, store app ] are now truncating contact Notes based on number of characters. Given that I might expect that is one reason why your many lines with just a 1-2 digit number followed by carriage return and line feed characters [ \r\n ] doesn't trigger this issue of truncating after a specific character count of Notes field content is reached.
I did a test with three of my contacts where Notes field got truncated sometime in the past year. While having cursor in Notes field I did a ctrl+a > ctrl+c and then pasted that into a character + word + line counting web app. The three I tested were showing 970, 986 and 992 characters, probably not accounting for carriage return + line feed characters [\r\n] what would add 2 more characters per line breaks.
So it seems around 1000 characters is the truncation point that has surfaced in the past year. Something I and others could test to see if a repro can be produced. It might not be classic outlook desktop app that is truncating I could be just opening for viewing in outlook.com web app and/or new outlook store app causes the truncation to happen.