iCloud Family 2TB storage kicking out members every month

Almost every month, iCloud 2TB being shared with family kicks out my family members, leaving them with “storage is full notices please buy a storage solution”. It is extremely frustrating to see and fix. And has happened numerous times. Requiring us to reset the family relationship and to add family back to the shared storage. This is an old problem I saw in an older thread that had only complaints and no solutions.

Here's what I have:

4 family members

1 unique iCloud for purchases and shares/ iTunes

Shared Storage with 2Tb adding up to 4tb on the Family Plan

Sometimes I can't use the Mac settings menu, but rather an Apple device to rejoin Family Plan Storage

[Re-Titled by Moderator]