Merge pull request #314727 from EngageCloud/docs-editor/sentinel-graph-provider-refere-1776197644

Update sentinel-graph-provider-reference.md

Author: prmerger-automator[bot]

articles/sentinel/datalake/sentinel-graph-provider-reference.md

@@ -883,7 +883,7 @@ Node builder after data source is set: configuration methods available.
 NodeBuilderSourceSet(alias: str, graph_builder: GraphSpecBuilder, source_step: DataInputETLStep)
 ```
 
-**Note:** Created internally by NodeBuilderInitial source methods.
+**Note:** Created internally by NodeBuilderInitial source methods. 
 
 #### Methods
 
@@ -979,6 +979,8 @@ Configure columns with required key and display designation.
 - Time filter column is automatically added if specified
 - Property types are auto-inferred from source schema
 
+- See **Restrictions** 
+
 **Example:**
 ```python
 builder.add_node("user").from_table("Users") \
@@ -2483,6 +2485,10 @@ builder.add_node("user") \
     .add_edge("follows")
 ```
 
+### Restrictions
+
+Builder support methods - add_node() and add_edge() does not allow use of underscores ('_') when naming nodes, edges or properties in a custom graph. Graph building operations will fail surfacing an invalid request error.
+
 ### Union Schemas
 
 Multiple edges with the same alias are automatically union'ed with merged properties: