observe(key).subscribe() receive multiple event when changing a value with Store()

[fascox]

Versions (please complete the following information):

• NgxWebstorage: 8.0.0
• Angular: 11.2.14

Describe the bug sessionStorage.observe(key).subscribe() receive multiple event after one store(key, value)

Desktop (please complete the following information):

• OS: win/macOS
• Browser chrome
• Version 108