Something unusual is happening with my cut and paste command, using the mouse. I ran the mouse over a section of text in one window and went to paste it into another window, when somehow one of the digits decided to change itself and it incremented by +1.. flickered, then went back to its original digit. This happened before when I cut and pasted data from a mathematical program, but sent the wrong answer (it was off by 1 digit) to my mathematical friend, who later asked me about my answer, since it was not correct.

Could a bug have gotten into this cut-and-paste operation?

What distro/version/desktop?

I use cut-and-paste and copy-and-paste multiple times every day and have not encountered anything of this nature.

It's a long shot, but, if you start two GUI applications from terminals, then try cutting and pasting from one to another, there's chance something useful will appear in one or the other terminal windows.

cut-and-paste does not perform calculations on the string.
Which softwares and OSs were involved?
Can you reproduce the behaviour?
How exactly did it "go back"?

There is also the question of hijacking the clipboard. It is especially easy if a page infected with javascript is allowed to run its scripts. However, injection of extra content can also be done using pure CSS. So you might be getting a backspace which then backs over the old number and overwrites it with a new number.

Edit: an example of hiding text: https://www.ush.it/team/ascii/hack-t...t_you_copy.txt

What distro/version/desktop?

openSuse Linux Leap 15.2 version, 64 bit
up to date on all patches.

I think this is close to the true answer. Something in the background running javascript might be hijacking the clipboard.

true cut and paste won't change anything, but it was almost spooky watching the digit change, then finally decide to go back to its original value

openSuse Leap 15.2 was the current linux.. and I don't know the version level of the cut-and-paste code.

I have only seen this twice now and it seems very infrequent.

I meant a digit displayed, like "6" then suddenly the digit went to "7", then flickered between "6" and "7" like it was trying to decide what to do, then finally went back to "6"

Very unusual behavior!

I'll climb way out on this limb and suggest it has nothing to do with cut and paste or any other software, but may be a failing bit in memory. The fact that it was changed in the file you sent elsewhere suggests the data actually changed. If the clipboard memory buffer were mapped into video memory and happened to have an unstable bit in the memory or the access path, it would account for both the flicker and the ultimately altered data. Unless malware were involved I would seriously doubt it is software related.

If it is a hardware failure you will find out soon enough, probably in other ways! I would suggest running memtest or other memory testing application and see if it turns up anything.

Until OP tells us more about the softwares involved I call shenanigans.
Not saying it never happens, but if I had a penny for every time somebody claimed they got hacked...

If the browser is involved, as was said, javascript etc., it's relatively easy to conceive that this happens. Then we need to know which site, which browser, etc.
Also, where exactly can you see the digits change? In a browser text entry? Again, which web page is that on.

If other desktop software is involved, I still cannot conceive how this can happen, esp. in a way that you see the numbers changing back and forth.
Again, I'm not saying you definitely didn't get hacked, but more info is required. Much more.