Object Stroke And FIll Disappear (Only Reappear In Isolation Mode)

[VivUwa]

Some objects in an illustrustration I created yesterday have completely disappeared.
When I click on their outline and open 'Isolation Mode', I see them perfectly.
How do I solve this...?
Thank you.
Screen shot attached.

[Ton Frederiks]

Cut, exit Isolation mode, paste?

[James238918936ba6]

 this work for you pls?

[Met1]

Your sample says Layer 26, any chance that something on the other (25?) layers is covering it?