One more test:

• I select America/Adak and click Save. The field below is showing -09:00 (counting from my local time, which is Europe/Ljubljana (UTC+2)).
• Then I select Other (specify offset) -> Save -> the field is suddenly showing the previous setting of America/Adak, which is -09:00.
• Then I select Australia/Adelaide -> Save -> the field is showing 09:30.
• Once more I select Other (specify offset) -> Save -> the field is still showing 09:30 of Australia/Adelaide.

Saving the previous time in new setting - but just in the case of Other (specify offset) - is the core of the problem (from my understanding). Luckily this is not happening when selecting Use wiki default (UTC). Previous time in the field is correctly reset to UTC in this case.

The problem is also in the name: If Other (specify offset) is the default setting of every new created account, then the word default should be placed somewhere in the name. But default is used in the option of Use wiki default (UTC). Now, if user is testing time zones, gets "lost in time" and tries to restore the setting, he is confused with those two options.

Wondering if this is the same issue as T132264 ?

@Aklapper I thing that @Nnemo has a different problem:

By GMT he understands the time zone geografically. By UTC he understands the time of that time zone, which indeed differs in Summer and Winter time.

• GMT is the time zone of Great Britain, Portugal and other states. It uses UTC (=UTC+0) in Winter time, but UTC+1 in Summer time.
• GMT+1 is the neighbouring zone that spans from France to Hungary. It uses UTC+1 in Winter and UTC+2 in Summer time.

So, as he sees Other (specify offset) and +02:00, he understands this hour as GMT, not UTC (and that would be the time zone of Finland, Ukraine and Turkey). Consequently he assumes he must change the hour to +01:00 to get the desired time of Europe/Paris.

CET and CEST, not GMT +1, in modern language.