Terminal keeps jumping to the top of the scroll buffer

I live in terminal emulators. The vast majority of Mac users do not.

When I stay live in, I mean I started with terminal access back around 1979 with real 80 column, 24 line physical terminals. I eventually moved up to a VAX/VMS workstation running DECterm terminal emulator. DECterm had a setting for how many lines to keep in the scroll back buffer. I've also use xterm on Unix based workstations.

I started using a Mac terminal emulator at work in 2005. I would sometimes noticed problems, such as the system getting sluggish as Terminal started to consume so much memory it started causing swapping. I looked around, and found it was my terminal emulator consuming all the memory (amplified when you have multiple windows and tabs open). So I looked some more and found preferences limiting the number of lines saved.

At work, I noticed other Mac users in Terminal using the too small fonts, and a host of other offenses because they were not bothering to learn the various Terminal preferences. So I wrote a work specific web page explaining all the more common preferences (including putting a limit on the number of scroll back lines), along with lots of information about ssh, how to bookmark ssh using unique Terminal Profiles, etc... The thing I found is that every Mac related book, public web page, Youtube video that talked about macOS Terminal spends about 5 seconds on preferences, expounds on the wonders of different color profiles, then ignores all the other preferences, and starts to explain the Unix commands. The people I work with know Unix/Linux commands very well, what they needed were using instructions on how to get the most out of the macOS Terminal emulator. The work web page is up to about 50 printed pages (most of it related to ssh connections to work development systems).

That is how I know about the preference/setting that limits the number of scroll back lines. Years and years of working with terminals and different terminal emulators. I actually spend most of my time using iTerm2, but I still maintain my work specific macOS Terminal web page, and it is visited about 5-10 times a day by someone in the company.

And no, I cannot export the page for you, or anyone else to read, as it has too much company specific information intermixed.

I do not have that issue, but as an experiment, can you try changing the

Terminal -> Settings (or is it still Preferences) -> select your profile -> Window (tab) -> Scrollback

and change it from:

Limit to available memory

to

Limit to number of rows to: nnnnn

and pick a reasonable number, such as 1000 lines, or even 10,000 lines, but anything except the default.