After implementing a custom probe, it would appear that the probe causes the route to be marked as invalid temporarily. Merely attempting the probe, by itself, causes the payment to not succeed.
Yikes. I guess we'll just stop doing probes in the meantime and rely on mission control's guesses.
Update: we are now using a manual probe because the destination variant of EstimateRouteFee does not support route hints (required for payments over private channels).
After implementing a custom probe, it would appear that the probe causes the route to be marked as invalid temporarily. Merely attempting the probe, by itself, causes the payment to not succeed.
Yikes. I guess we'll just stop doing probes in the meantime and rely on mission control's guesses.