We have seen the same issue and have not resolved it - you say you are running the UBEs on the server - are you running them in a vb script or command file of some sort?
I use vb script and I think it relates to how the jobs are submitted, if they are submitted to batch, the logs appear to be correct, interactive and this is where we usually see the problem with the wrong logs, no logs at all, etc.
Trying to control single threaded jobs and dependencies is a PITA with out using interactive mode.
We have also found out the interactive mode does not care about single threaded queues. If a user submitted job is running in a single threaded queue and you start a job from a vb script in that same queue in interactive mode, they both will run at the same time!
Not good for things like R42800.... I did it and it took a full day to clean up the mess.
I have been toying with a modification to my script that will submit all jobs to batch but query the F986110 until it finishes before I submit the next job to resolve these issues but have not implemented it yet.