If that happens again, next time just press Ctrl+Z. Segments won't get stored in your TM when that happens.

By the way the culprit is selecting across paragraphs backwards (from the active segment to the previous one). It can be even invisible for you when you select the active segment and just slightly move the mouse up against the previous segment. In this scenario nothing seems selected in the previous segment but it is enough to trigger the effect.
When you select from the active segment to the next one, it won't happen.

Stepan Konev 

I've suffered this effect as well, and always thought that I must have pressed inadvertenly the default shortcut to select all segments (SHIFT+ALT+A)…

I followed your procedure, but I can’t replicate it. Could you please elaborate so I can repro it? Thanks!

Probably this video can help. 

Jesús Prieto said:

Could you please elaborate so I can repro it?

Click at the end of a segment, don't release the mouse button, move the mouse up so that the cursor is against the previous segment. Release the mouse button. Press Ctrl+Enter.

 Thanks Stepan Konev 

Oh my… I can repro it in my Trados Studio 2022. Dragging across paragraphs with the mouse, and then confirming causes the effect.

Edited: To repro it, you can confirm either via the shortcut key to confirm (CTRL+Enter or ALT+Add) or with the Confirm button.

 Paul  Were we aware of this?

 Thanks Stepan Konev 

Oh my… I can repro it in my Trados Studio 2022. Dragging across paragraphs with the mouse, and then confirming causes the effect.

Edited: To repro it, you can confirm either via the shortcut key to confirm (CTRL+Enter or ALT+Add) or with the Confirm button.

 Paul  Were we aware of this?

 Jesús Prieto Stepan Konev 

I certainly wasn't... but I can repro in 2024.  I'll make sure this is logged.

Thanks Stepan... that was helpful and a bit of a mystery potentially solved!!

Although it's almost a feature!!!

Paul  A very nice feature, yeah, quickly confirming all segments below, even if they are empty!

Jesús Prieto 

Jesús Prieto said:

even if they are empty!

Indeed... it's a productivity feature that also saves time on the translation ;-)

This has been a bug since Studio 2009. I reported it here: community.rws.com/.../confirm-multiple-segments-bug

John Fry 

I’m not certain when this issue first arose, but I appreciate you bringing it to our attention again.  After reviewing our backlog, we found it had indeed been logged under the reference CRQ-16803 (shared here for future reference), with reports dating back to 2017.

The reason it likely hasn’t been resolved is not due to an inability to fix it, but rather because it tends to get lost in the shuffle of priorities.  The issue seems to occur under less common or unsupported circumstances, which is probably why it hasn’t been seen as a more general problem impacting enough users to elevate its urgency.  That said, there’s a simple workaround if you notice the issue – as Stepan Konev  pointed out, pressing Ctrl+Z twice should resolve it.

We’ve added a comment to the existing report, and the development team may be able to address it while working on related parts of the software.