About half the world has winter/summer time and half the world does not - which makes international scheduling always a bit challenging.
Most of Europe will switch to Winter Time this weekend on Oct. 27th. The US will do so on the 3rd of Nov.
If you have Flexi Classes booked in the next few weeks, make sure your time zone is set to the correct time zone you are in. If you have it set to your time zone, the winter/summer time change will already have been accounted for and everything will work perfectly. However if you chose a time zone that is currently the same as yours, it might not be the same as yours next week anymore.
Mexico for example stopped using winter/summer time two years ago, so if you are in the US and currently have the same time as someone in Mexico, you most likely will not have it anymore in two weeks.
It is all pretty complex, but in general, just make sure to have the time zone chosen under Settings that you are in.