My bad bliprock, I think you're right, it's not a bug rather "user error" due to that boring LOOP ON/OFF behavior.
My step by step was too rough. In fact my default sequence is 2 bars so I go from 2 to 4 bars. Problem is when I do this LOOP becomes OFF and if you paste something at the last bar when LOOP is OFF a new bar is automatically added. Another boring behavior for me

To make a short story long, The step by step was a simple way to describe that "behavior" and I had to face it in a more complex way.


I think I know where my mistake comes from. I reopened an old project. I didn't really remember how it was built. In this project the 4 first bars are 3/4 and there's a graphic bug as you can see on one screen shot. Sadly there have been problems with others time sig. than 4/4 with the grid edit since the beginning.
I'm not sure but I think it can have some consequences on the following bars. On the other screenshot (which was taken after paste at the last bar in order to show more graphic weirdness) you can see that the cursor in the grid is at 37.01.00 but the cursor on the bar field is at bar 36. I think it can lead to mistakes too.
So to sum up the main idea, lots of small workflow issues that made me lost

Another boring issue to conclude, if you reduce one bar at bar 37 to make the whole thing 36 bars, it automatically returns to bar 1 after processing. That can be frustrating too.