Usage of beginoftheweek in combination with usage of floor

In an app the statement '[%beginoftheweek]' is used to get the starting day of the week. This starting day of the week is later on used to determine the day with the statement floor. This causes in daylight saving time that the day before is taken.  E.g. Begin of theweek of this week is 25-03-2018 22:00:00. With the floor statement the determinde day is 25-03-2018. For some reason it is ok when it is not daylight saving time but with the use of daylight saving time it is not correct.  Begin of the week of last week is 18-03-2018 23:00:00. Is my conclusion that the floor statement only works when it is not daylight saving time correct? Or is the statement floor incompatible with datetime fields? The datetime is all in utc and the loacaltime is Amsterdam time. 
1 answers

What happens if you use [%BeginOfCurrentWeekUTC%]? Make sure you also use non-localized DateTime attributes if the time part is not relevant. Furthermore, also use the UTC functions, such as addDaysUTC().