The JCR browser allows me to edit properties of nodes.
When I change both the property name and value, only the name is changed. I must repeat the action to change the value.

To replicate:
In the JCR browser, add a new property to an existing node.
Select the new property and use the "Edit property" action to open an editing dialog.
Change the name and value of the property and save.
Only the name will have changed.

Open the dialog again and enter a value.
Now the value will be saved.

Open the dialog a third time and change the name and value.
Again, only the name will be changed.