More info: As a workaround, I've found that eventually if I tap enough times it will work, and you'll know because the circle actually goes bold/highlighted.
Tap Faction Name the first time - User Name/ID circle stays highlighted and active, search will not work as expected:
[image: puu.sh]Tap Faction Name, then Places, then Faction Name again ... repeat if needed until highlight changes, search will now work for Factions as expected:
[image: puu.sh]And, this is also the case for other radio buttons, for example when changing graph intervals (24h / 7d / 1m / etc) on the Detailed Stats or Stock pages.
I'm also using Chrome for Android, and this has persisted across 3 different phones for me now.