I’m not affiliated with balajisundarajan8 so not answering the question for him.
I have the same issue (6.8.0) and created a reproducable scenario with the flowable docker image for 6.8 on dockerhub. See this topic: HTTP task execute parallel in same transaction not working in 6.8.0 - #4 by CElbersen
If I’m not mistaken that image uses spring boot.
I’ve also tested this with an image running longer than 1 hour.
I did not yet try it with 6.8.1.