Why are new photos no longer added to my shared albums? How do I fix?

I got notifications on my Macbook air that users in my shared albums were adding new photos. When I went to see them on my iPhone, they were not there. The last new photo I could see was from several months ago.

Then, I searched for an answer to why I wasn't seeing new photos in my shared albums on iCloud. A "community specialist" advised that you can turn off photo sharing and be assured the shared albums would come back when you turn it back on.

They did not come back. 😢

I lost all of the albums that I shared (which others contributed to) as well as albums that were shared with me. This is a major setback. I've asked my friends and family to share those albums with me again. I fear I will never get some of those photos and videos back.

Does anyone have a fix for this bug?