Process Instance status not completed when its all tasks completed

Dear expert,
I encountered a weird issue when I use the activiti-engine with 5.21.0. in my project.
I found the one process instance status was not completed, but its all related tasks were completed.
Then, I look into the log. It is supposed that the endEvent is executed at the end of the sequence, but it seemed endEvent had been executed before as opposed to the flow itself.
I attached the log.

Unfortunately, I am a new user, so I can’t attach more media such as flow as a screenshot here for the time being.
Maybe I can send an email to you regarding other information if someone can help me out.

Thank you