I've checked with our webmaster on this issue - it seems like the issue might be on Feedly's side as we can see that on our side everything is updating properly. We've also tried limiting the number of elements to 10 but, unfortunately, this did not solve the issue with Feedly.
For Basic accounts, the max polling time can vary between 30min to 1 day depending on how popular the site is and how often it publishes.
In this case, especially, since there are no specific errors shown for our content on Feedly's side but the content is not updated on Feedly, we assume that the issue is somewhere on their side. Unfortunately, seems like "Basic" users cannot contact their technical support, but if you have a paid plan on Feedly and especially if you have other subscriptions through Feedly and they work properly, then we recommend that you contact their technical support directly and ask them to investigate the issue. Unfortunately, we cannot guarantee how other services work, nor do we have any control over it. Sorry for the inconvenience.
Thank you for the detailed accounting of the issue. I could not see the update on May 13th. It's been more than one day since I last tried though and the update still does not show up. This definitely seems like a feedly issue, since a day has passed and the update does still not show up.
Granted, according to feedly, only one other person has subscribed to this feed. Still according to them, one day would be the maximum to re-fetch information from the site. Not sure if some https caching here is at play.