you should open a support ticket with SDI am experiencing the same issues on a qnap TS-231P with the dual core arm. Firmware ver 4.3.6.0805 I installed the latest qpkg 0.9.35, I can see the web interface, I can open the app on my phone and it recognizes that there is a DVR package associated to my tuner. I can schedule shows and such, but as soon as I hit record, or a timer goes off to record, the record engine crashes.
something is clearly wrong, as the engine shouldn't be crashing for a record event.
SD should have better diagnostics as to why the engine is crashing..
check memory, drive diagnostics, space, etc..