BB Passport: calendar entries one hour off -- why??

Hi! I realize there are plenty of threads dealing with "one hour off" issues, but apparently none that fits my specific setup (sorry if there is one I missed).

All calendar events in my BB calendar are shown 1 hour early. For example, when I create a meeting at 3PM, it shows as 2PM in my BB calendar (even immedeately after creation of the event). However, it only shows the wrong time on my BB; it's the correct time in Outlook and in outlook.com (I sync my BB calendar with my outlook calendar via an outlook.com account). It also doesn't matter whether I create the event on my BB or in Outlook (there are threads where people seem to only run into problems when creating appointments on their device, but not when creating in Outlook; that's why I'm pointing this out).

Here's my setup:

- No BES, no company server, just plain personally used BB Passport (bought unlocked via Amazon, so no carrier messing with the software/OS) synched with an outlook.com Account (so all synching happening OTA, no desktop/USB synching taking place)

- BB OS 10.3 (would prefer not to update to 10.3.1 (b/c of lack of Flash support), so hopefully not an OS version issue!?)

- Outlook 2013 (as part of Office 365)

- Timezone is Berlin (GMT+1). The timezone, as well as date and time, are correctly set on my BB, on my Computer/Windows (auto-synch with time.windows.com), and in my Outlook account

- Daylight saving time is also set up correctly (and working) everywhere

- Time format on my BB is 24h (I'm pointing this out since some folks seem to have fixed "1 hour off" issues by setting from 12h to 24h format)

- Not willing to "simply set another timezone on the device". I'm not looking for a workaround, I'd like a proper solution for this issue.

- Issue appeared only since I got my BB Passport. Was on Z10 and Q10 before with no issues (with the same setup, except of older BB10 OS version, of course).

I'm completely out of ideas... anyone know what might be the problem?

Thanks!