There is an issue with Opendelta, so that's why it just goes into recovery instead of applying the update.
While it gets fixed, you need to:
_ once in TWRP, click on Install
_ navigate to /sdcard/Opendelta
_ select the nightly ZIP file.
_ on the next screen, uncheck the zip verification box.
_ swipe to install the update.
_ click on wipe dalvik/cache
_ reboot system
Sent from my Find 5 using XDA Premium 4 mobile app
Oppo Find 5 Midnight 32GB
OmniROM 4.4.2 - NIGHTLIES