Using Outlook for Android in business environments for email and scheduling
Frglx posted a screenshot on the 5th of November, almost 2 weeks ago, from the current version of Outlook for Android that shows the option to disable this behaviour!!!
Version 4.2044.3 has a "Use default browser" option right down at the end of the Settings panel within the app.
It was bad enough reading some of the ridiculous conspiracy theories people were posting about this annoying "feature" when it first turned up, but now that the issue has actually been addressed, people who can't be bothered to read the earlier posts are still complaining about it!
You don't need a workaround anymore. You can just turn the "feature" off!