I get the impression that they're getting into a state now where there's probably an "expectations mismatch" between what people expect to be doing when they set up a recurring donation compared to how Liberapay actually works.
As the blog post mentions, now you can say "I want to donate $5/month" and you put in $60 to cover a year, but you have to pay that full $60 immediately, and the recipient also receives the whole $60 (minus fees) right away as well. After that point, there's not really any way for the donator to change their mind and stop donating after a few months, so it's more like a one-time donation with a reminder but still being presented as a smaller recurring one.
I think the problem is that overall it will end up encouraging people to make smaller donations for shorter time periods because they won't necessarily want to commit for many months or years' worth up-front. Then that means that they have to be sent reminders to re-donate more often, which feels more annoying and will probably result in people just letting their donations lapse more often than repeatedly renewing them.