...
I'll do some more testing, including setting and deleting one-off recordings.
'One-offs' aren't being removed for me.
I just tried it and I had the same, that a one-off wasn't deleted from the Beyonwiz, because the update list from IceTV didn't have the timer "forget" entry.
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To form part of a test, I sent a single timer from the web page and it was received on the T4.
I identified two more timers I could remove from the T4.
I waited two full fetch cycles, and then via the web page, I removed the one-off timer above, and an existing single episode of a keyword recording, and an existing single episode of a series recording.
On the T4, two of the three timers were deleted; for episodes from (i) the series recording and (ii) from the keyword recording - as expected, given the issue we're experiencing, IceTV has left the one-off single recording timer remaining on the T4.
If IceTV support are interested -
ice_timer_id="1499821305" (one-off timer not removed)
ice_timer_id="16308666889687844388"
ice_timer_id="16308667886170571913"
Cheers,
Geoff