Hi again,
Just going over it again I noticed you are talking about the summer and wintertime.
That is not a glitch. The data from the app is one, it is bars.
It is about if your broker actually changes it or not. Some brokers change it, others do not. Some synchronize it with your local time.
So a solution is to set your time on the computer to UTC, and then install a new MT platform and see if the broker will synchronize it.
If it does, great, you will have the perfect match in the data.