@Katriin -
Same with my iPhone. It happens as soon as one measurement goes past 56-57%.
As an application developer, myself, I can almost see how this happened. Someone told the developers that "normally" any one measurement will rarely reach 55% so they coded for that plus a little "smidgen".
Thankfully they placed the percentage indicators to the left.
Luckily the web base sleep graphs do not have this limitation. Kinda expected, as there is more screen real estate to deal with.
@Katriin -
Ahhh - kinda hard to call it a bug, while even I, as a programmer myself, want to.
While not trying to get too philosophical here, applications, like life, are full of trade-offs. To make it so everything would always fit, no matter the percentage, with a full description to the right, a quick estimate would be to have the scale at 50% of what it is now.
Actually that wouldn't be too bad and the font for the labels and time could stay the same font size and weight. I'd vote for that!
But I can almost guarantee a lot of people would complain because some of the bars were so little and there is so much room left on the right.
Tradeoffs, tradeoffs, tradeoffs. The life of today's application developer. And yesterday's too. I've been doing that kind of "thing" for nearly 40 years.
Happy Holidays.