Series60 making engine noise issue

Hello everyone.got 2009 westernstar with series60 14l DDEC 6.it’s getting noise from back of the valve cover.last time doing an overhead the technician found that jakes settings were too tight.after making adjustments on the overhead the noise went away.but after about 15000 miles it came back.roughly 60000 miles on the rebuild and month left on warranty.technician told me if the noise comes back we’ll have to rebuild the jakes on it.i want to know, can this issue occur with bad jakes or something else is going on with the valves or rollers?Truck runs fine and no check engine light.and i am in indianpolis at the moment anybody know good Detroit mechanic in this area please let me know.i want to get second opinion.thanks!
Below is the link to the video of noise.
https://youtube.com/shorts/ZVKpxmI7s54?feature=share

 

Anybody??

 

Got million miles on the truck itself.the jakes were not rebuild during the overhaul.how big of job is it to rebuild the jakes on series60?and can i continue to drive it for like another 1500 til i can get it to the house to fix it?

 

Ok.appreciate it.this gives me some peace of mind lol