CAMEL-25068: camel-core - Docs: a RouteTemplateContext reused for several routes shares the template beans of the first route

Review of apache#27466: the template beans bound for the first route are kept in the
RouteTemplateContext and are then seen as beans of the caller, so the later
routes share them. Say so in route-template.adoc and the 4.23 upgrade guide.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: allthingssecurity

docs/user-manual/modules/ROOT/pages/camel-4x-upgrade-guide-4_23.adoc

@@ -503,6 +503,9 @@ The `org.apache.camel.processor.InterceptSendToEndpointCallback` class is deprec
 - A bean bound by `TemplatedRouteBuilder.bean` or in a `templatedRoute` is now used instead of a `templateBean` with
   the same name, which is no longer created. Prior to Camel 4.23 the template bean replaced it when both had the same
   type, and was used when the route looked the bean up by the type of the template bean (such as `process("myBean")`).
+  When the same `RouteTemplateContext` is reused for several `addRouteFromTemplate` calls, the template beans bound for
+  the first route are now kept as beans of the caller, so the later routes share these instances instead of each
+  getting new ones. Use a new `RouteTemplateContext` per route to get new template beans for each route.
 
 === camel-aws2-ddb
 

docs/user-manual/modules/ROOT/pages/route-template.adoc

@@ -654,7 +654,9 @@ See xref:route-template-bean-binding.adoc[Route Template Bean Binding] for detai
 
 A bean that is bound when creating the route (`TemplatedRouteBuilder.bean` or the beans of a `templatedRoute`)
 takes precedence over a `templateBean` with the same name, which is then not created. This allows replacing a
-template bean, for example with a mock in a test.
+template bean, for example with a mock in a test. The template beans are bound to the `RouteTemplateContext` too, so
+when the same `RouteTemplateContext` is reused for several `addRouteFromTemplate` calls, the routes after the first
+share the template beans created for the first route; use a new `RouteTemplateContext` per route to get new ones.
 
 == Configuring route templates when creating route (advanced)