I conducted another experiment:
1. I created a custom property called "Property 1", and made it Binary, with default=false.
2. Created two nodes, and entered values of "Property 1" as True for one node. The second node took the default value of False.
3. Edited the custom property to be decimal, with default value of 10.
4. Checked the nodes that I had already created. The values of the property had changed for both the nodes: The first node, which had a value of TRUE, now has a value of 1. The second value, which had a default value of 0, now has default value of 10.
5. Changed the label of the property, from "Property1" to "XXX". Now both nodes show the property as "XXX". The old label is nowhere to be seen.
All this is logical.
6. The Properties manager also shows only one Data source: XXX. (apart from the URL and Tooltip). This also is logical.
So how did the Properties Mapper behave differently in my earlier experiment??