The method \Drupal\state_machine\Plugin\Field\FieldType\StateItem::dispatchTransitionEvent uses $workflow = $this->getWorkflow() and right after uses $workflow->findTransition().
The problem is that the method getWorkflow() can return false. In that case, we'll get a the error mentioned in the title.
I can reproduce it in a very specific way that is not really interesting.
Just by looking to the code we ca see the problem.
Check if $workflow an instance of WorkflowInterface before using it in $workflow->findTransition().
Active
1.0
Code
@niharika.s your MR is failing the if conditions are not correct
The fix addresses the issue where $workflow could be false, leading to an error when calling $workflow->findTransition(). By ensuring $workflow is an instance of WorkflowInterface before using it, the code now handles cases where the workflow is invalid. This solution should resolve the issue.Thus Moving this to RTBC.