Family Sharing enabled, but device reverts to 5GB, says iCloud is full, and mail stops working

I’m posting this because I keep seeing replies that don’t address the actual issue. This is not about someone misunderstanding how Family Sharing works. This is a recurring problem where a family member’s device stops recognizing shared iCloud storage.

Here are the facts in my case:

1. Family Sharing is active
2. The Family Organizer has a 2TB iCloud+ plan with plenty of space available
3. I am NOT the organizer — I am a family member
4. I have accepted the Family Sharing invite
5. I do NOT have my own separate iCloud storage subscription
6. My device is an iPhone 16 Pro running iOS 26.2

Despite all of this, my iPhone suddenly shows:

• Only 5GB of storage
• “iCloud storage full” warnings
• Prompts to purchase my own storage plan

At the same time:

• Other Family Sharing features still work
• The organizer’s 2TB plan is still active
• There is still plenty of space available in the shared plan

Additional serious impact:

When this happens and the device thinks storage is “full,” iCloud Mail stops working. I cannot send or receive email until the Family Storage connection is restored. So this bug is not just cosmetic — it disrupts core iCloud services.

The only way this gets fixed is by:

• The organizer removing me from Family Sharing and re-adding me

OR

• Going into settings and trying to force the device to re-recognize shared storage

This has now happened multiple times, and it always comes back.

Why this is clearly an Apple issue

A Family Sharing member should not be:

• Dropped back to the free 5GB tier without warning
• Told to buy their own subscription when shared storage is available
• Forced to rely on the organizer to repeatedly “reset” Family Sharing
• Blocked from using iCloud Mail because the system incorrectly thinks storage is full

The system should automatically:

✔ Keep the member tied to the shared storage plan

✔ Present a choice if storage is actually full: Use Family Storage or Buy Your Own Plan

Instead, the device behaves as if Family Storage does not exist, which leads to failed backups, service interruptions, and unnecessary subscription prompts.

This appears to be a sync/association bug between Family Sharing and iCloud storage, and it needs to be addressed at the system level — not treated as a one-off setup issue.

If others are seeing the same thing (family member, not organizer, shared plan active, but device falls back to 5GB and iCloud Mail stops working), please reply so Apple can see this is widespread.