So this is a week old flash of 5.1.020. This doesn't happen very often (this is the 2nd time) as I usually have enough tuners but last night it ran out of tuners when starting timer recordings and didn't respond to the remote and the spinner appeared.

I have total of 4 tuners (all internal) DVB-C only. I had all the tuners used up (3 for recordings and 1 for current live feed). Another timer recording started and got a brief message on screen about not enough tuners. Then the spinner appeared, live feed and sound continued to run but... Had to power off the box. After reboot all the recordings resumed but there was a zero-size recording in addition to the growing one.

I have a debug log snippet. If you need any other files or more of the log, please let me know. The log is quite big since I've had it on for some time now.

Code:
<813055.493> [eEPGCache] nownext finished(1522090938)
<813055.493> [eEPGCache] stop caching events(1522090938)
<813055.494> [eEPGCache] next update in 60 min
<813065.484> [eDVBServiceRecord] pcr of eit change for event 28306: 115ea24ba
<813065.484> [eDVBServiceRecord] now running: Kuppilat kuntoon, Jyrki Sukula! (3600 seconds)
<813065.484> [eDVBDemux] open demux /dev/dvb/adapter0/demux1
<813065.484> [eDVBSectionReader] DMX_SET_FILTER pid=18
<813098.265> [eDVBServicePlay] timeshift
<813098.266> [eDVBServicePlay] timeshift
<813127.604> [eDVBServiceRecord] pcr of eit change for event 26097: 122057a5d
<813127.604> [eDVBServiceRecord] now running: The Walking Dead (16) (3600 seconds)
<813127.604> [eDVBDemux] open demux /dev/dvb/adapter0/demux0
<813127.605> [eDVBSectionReader] DMX_SET_FILTER pid=18
<813127.607> [eDVBServiceRecord] pcr of eit change for event 26097: 122058165
<813127.607> [eDVBServiceRecord] now running: The Walking Dead (16) (3600 seconds)
<813127.607> [eDVBDemux] open demux /dev/dvb/adapter0/demux0
<813127.607> [eDVBSectionReader] DMX_SET_FILTER pid=18
<813136.658> [RecordTimer] activating state 1
<813136.660> [RecordTimer] Found enough free space to record
<813136.662> [RecordTimer] Filename calculated as: '/media/hdd/movie/20180326 2204 - Nelonen HD - Elokuva_ Beck_ Sairaalamurhat (12)'
<813136.662> [Navigation] recording service: 1:0:19:3331:1F:0:FFFF0000:0:0:0:
<813136.663> [eDVBResourceManager] allocate channel.. 001f:0000
<813136.663> [eDVBResourceManager] available channel.. 0002:0000
<813136.663> [eDVBResourceManager] available channel.. 001a:0000
<813136.663> [eDVBResourceManager] available channel.. 0019:0000
<813136.663> [eDVBResourceManager] available channel.. 0011:0000
<813136.663> [eDVBServicePMTHandler] allocate Channel: res -6
<813136.663> [eDVBServiceRecord] RECORD service event 0
<813136.664> [RecordTimer] 'prepare' failed: error -6
<813136.664> [RecordTimer] backoff: retry in 5 seconds
<813136.664> [eDVBServiceRecord] stop recording!
<813136.664> [eDVBServiceRecord] (was not recording)
<813136.665> [Trashcan] Recording(s) in progress: 4
<813136.667> [RecordTimer] prepare failed
<813136.667> [eDVBServicePlay] timeshift
<813136.668> [RecordTimer] zap without asking
<813136.684> [Skin] processing screen MessageBoxSimple:
<813136.721> [Skin] processing screen MessageBoxSimple_summary:
<813136.728> [RecordTimer] ok, zapped away
<813139.323> [gRC] main thread is non-idle! display spinner!
So it did try to zap, but something went wrong. I found a similar thread here: http://www.world-of-satellite.com/sh...without+asking but didn't really see a solution or cause. In my case I only use 1 favourite list, no additional bouquets etc. and no auto-timers.