Sentry not evaluated on case instance variable change

I have a simple case model for experimenting where I am using a milestone to complete a task.
For the milestone I have an entry sentry with an if part which references a case instance variable “isResponseComplete”. This variable will be set to false initially. It will be changed to true after few tasks are executed. According to the docs, sentry evaluation takes place When variables related to the case instance change (added, updated or deleted). But in my case it doesn’t. Even after changing the variable the milestone is not activated or occurred and it is still in available state. The same behaviour is applicable for the tasks as well which is working as expected. When the variable is turned to true, all the tasks become active. But the milestone is not occurring. Please help me to understand what I am doing wrong here.uploaded the cmmn file for reference. And I am Changing the case instance variable from java code like runtimeService.setVariable(caseInstanceID,“isResponseComplete”,true)

Feasibility.cmmn.xml (8.0 KB)