It might be a bug itch.io has to fix or your not doing something right. Try double checking to see if the bundles still show.
I checked the sale settings and one is set to require one project to be owned. And it shows for me. Does being the creator mean I own it?
It's this one, showing - 30% sale for me:
https://bl4cksh33p.itch.io/root
Did anyone ever have multiple bundles / sales shown on a project page? If usually only one is shown it would be nice to have all of them listed.