Default [Q] KitKat 4.4.2 OTA upgrade

Hello,

My Nexus 7 was on stock 4.4 Kitkat rom, with TWRP 2.6.3.1 and rooted. Some time ago I received a notification about the 4.4.2 OTA upgrade, in which I accepted in no time. I could see that it is like that TWRP handled the package installation, but after that the tablet just returned to TWRP after reboot. I have also tried powering it off and started it again, still no luck.

Grateful if you can provide me some advice here, many thanks.