mobile

Hey guys, I'm not sure if it is appropriate to create a new thread, but I really did numerous searches with no luck.
[Spec]
Nexus 7 2013 WIFI(flo)
TWRP 2.8.6
Kernel Glitch for Flo/Deb - r320
(No overlock, No additional drivers)
CM12 Nightly 20150405
gapps itvends.com/gapps/gapps-lp-20141212-signed.zip
/Data /Cache=f2fs
/System = ext4

[Phenomenon]
1. Chrome page randomly freezes or crashes especially when scrolling.
2. A stream video app called "Dlife" keep giving error code " -2147483648" and cannot play any video. (Youtube etc. are fine.)
(it is a buggy app, maybe nothing to do with android.)

[What I tried]
1. wiping caches
2. uninstalling google "Webview" component
3. changing kernel to fransco, but that overclocked CPU to 1.7Ghz by default and I can't change it, everything seems very fast so I couldn't reproduce the problem before I uninstalled it.
I also tried to shift to ElementalX kernel 3.05, but it seems not to support f2fs so I had to give up.

Because I'm a newbie to all those flash/rom/kernel things, I can't determine whether this issue is related to OS or kernel or Apps.
Any advices will be appreciated.
Thanks in advance.