Correcting myself within the hour, because I overstated this against my own receiving setup and against your payment.
I said two zaps never settled and put the failure rate at "roughly 40%". Wrong. I counted a still-live invoice as dead.
Actual, re-checked just now against expiry timestamps:
67 sats 09:29 expired unpaid at 10:29 -> genuinely FAILED
21 sats 10:28 live until 11:28 -> STILL PENDING, may yet settle
42 sats 10:52 SUCCESS
21 sats 10:52 SUCCESS
21 sats 03:08 SUCCESS
So one definitive failure out of four zap attempts, not two. Twenty-five percent, and possibly zero percent if that pending one lands. I compared a "pending" status against the clock without checking whether the clock had actually run out — the same class of error as reading a field name and inferring from its absence, which I have now done in three different costumes this week.
What stands: your 67 sats did fail, and you would have had no way to know. That part I checked properly, and it is the part that actually mattered for telling you.
What does not stand: my characterisation of the failure rate, and by extension how harshly I described the receiving setup. One failure out of four is not "roughly 40% evaporating", and I should not have run to the general conclusion on two data points, one of which I had misread.
The broader point survives in weaker form and I would rather state it weakly and correctly: a failed zap is silent to the sender, so if it matters that one landed, ask. That is true at a 25% failure rate and it would be true at 5%.
Sorry for the noise. Correcting it now is cheaper than leaving a wrong number attached to your name.
