Sometimes, using the ‘P’ (Locators to selection) shortcut will not select the full part selected video attached.
This is again an intermittent bug, did not happen frequently so far.
To make sure it’s possible for people to reproduce and eventually make a bug report to the devs, please format your bug reports like this: How to format a bug report.
I don’t really get what you are showing with the video. It doesn’t look like you are showing steps to repro your issue.
I spent enough time and documentation on it. The bug is clear and intermittent, I am a developer myself and would not need more to understand the bug.
I did no pay regularly for this software to spend a lot of time reporting bugs BTW, so please feel free to format it yourself if you’d like.
I have edited to title to correct.
Thank you for editing the bug title, to be clear and as mentioned at the end of my report, it does not happen frequenetly though, but when accumulated with other intermittent issues; it is still frustrating of course.
This issue never happened to me - ever. I have no idea how to reproduce this. Maybe this is not a general bug but something more related to your project/preferences/current installation.
No it is not related to my project because it is using the same empty template i use all the time.
The locators were placed at exactly the start/stop of the C3 note in the part. The note may have been selected when you initially hit the P?
@TakashiWatanabe Interesting hypothesis, but I don’t think so because, when I selected the part in the end, it automatically would have deselected notes of the start part and one thing I am certain is that I was selecting and then looping on what was my current (ending) loop before the buggy transition and then i could have have eventually edited notes on the ending part, but they would have been deselected too as soon as I selected the starting part (double-checked that scenario too).
And what is also certain is that i did not select other notes from the starting part that was not playing, just clicking on that part itself then pressed p in the arrange window, then selection did change but not as I expected and also it was selecting the end of this starting part so it could not be the ending part notes?
The video does not show what happened before the bug, but what happened before was that I was looping in play mode on the last part and I remember i did edit notes from this part on the bottom track but as the video shows, it is far away from the new selected area.
Thanks for the idea though did not even know that this feature existed, it could have been that: the selection really looked like my C3 note there.
EDIT: I’ll mark it as a solution for that one in doubt because the selected area really matched the note and while I switched apps to capture a video it could have been de-selected, so giving the benefit of the doubt here 
I’ll re-open it if it happens again and I can be 100% sure no notes was selected but for now I want to believe @TakashiWatanabe was right.