Time blocks and the hours (scale on the left) of the weekly calendar lose alignment after daylight savings. In the image you can see that the blocks appear shifted back by an hour relative to their actual times:
It actually seems to be the day’s hours that have been shifted, since my “working hours” are also off by an hour.
My TZ is MESZ, in case that matters.
It looks like the issue is tied to the setting “First day of the week”. When the first day is Sunday, the blocks are shifted by an hour. When the first day is Monday (or Friday) everything appears to be normal. When the first day is Saturday the calendar breaks completely–no blocks and no lines, just plain white.