Here is the Top 10 external bugs of Flash Runtime in Jan 2012, which is order by incoming votes in Adobe bug base:
1. Mac OSX Player Issue: kernel: IOSurface: buffer allocation size is zero
The log file (kernel.log) gets flooded with "kernel: IOSurface: buffer allocation size is zero." messages.
https://bugbase.adobe.com/index.cfm?event=bug&id=3077658
2. iOS and Android Native Scroll
https://bugbase.adobe.com/index.cfm?event=bug&id=2958123
3. Flash 11 showing black shapes in BBC iplayer
https://bugbase.adobe.com/index.cfm?event=bug&id=3008910
4. Video not working correctly for Air 3.1.0.556 on Android ICS
https://bugbase.adobe.com/index.cfm?event=bug&id=3100560
5. choppy audio and video on xoom with android 4
https://bugbase.adobe.com/index.cfm?event=bug&id=3099866
6. The Flash Player settings dialog is not clickable in Mac 10.7 – Lion
https://bugbase.adobe.com/index.cfm?event=bug&id=2942091
7. Flash Player 10.3.183.5 Shared library/gotoAndPlay() or gotoAndStop() bug
https://bugbase.adobe.com/index.cfm?event=bug&id=2940617
Resolved: Fixed In Build 10.3.183.7
8. Way bigger app file size once app is published to iTunes
https://bugbase.adobe.com/index.cfm?event=bug&id=3014058
9. URLLoader doesn’t work(IOError #2032) in AIR SDK version 2.6
https://bugbase.adobe.com/index.cfm?event=bug&id=2881807
10. Flash Player crashes when playing back youtube videos with EnableLinuxHWVideoDecode enabled
Resolved: The EnableLinuxHWVideoDecode feature is removed, suggest not use EnableLinuxHWVideoDecode.