Useful or not, from you.
lightning MPP pay splits into too many subpayments

I have an outbound channel with an BTC to Lightning exchange worth 2.000.000 satoshi, with enough capacity. I try to swap my 2.000.000 satoshi for the same amount, but on-chain. Lightningd splits the payment into too many subpayments, and eventually fails, even though the destination is only one hop away, and has enough capacity.

That's a useful answer
Without any help

I just wrote pay bolt11, no extra parameters. I can probably wait for #3917 before attempting any more pays. I've sent you guys some logs.