My app is a classic project that I maintain since Ti 2 or 3.
Recently I have bumped Ti SDK to 6.1.0.GA and I'm making some adjustments to build the final version.
Like other bugs like this (https://jira.appcelerator.org/browse/TIMOB-24801), I found a bug on android that makes the tabgroup lose color, and the property doesn't seem to work anymore.
I also have read thoroughly the changelog of 6.1.0.GA and nothing regards changes of tabgroup behavior.
I don't have the time to provide you a testcase and isolate this, but I'm pretty sure this will be easy to identify.