PROBLEM SOLVED!
I have gone over two weeks with this issue recurring since
I changed my two non-detached jobs to run as detached.
Thank you.

: I think the best path is to find if this problem is linked to specific jobs.
: Another "quick" try is to set all jobs to run detached. This can
: be done using a script job. If you have 24x7 running in the Master mode
: (e.g. as server) then you can have a job that remotely updates jobs on all
: servers. Definitely more options are available in 3.4.24 then in 3.3.8.

: Because you are running it on a large number of servers it makes sense to
: maintain single global log. Having single log for all servers you can
: faster find if there are any job dependencies or common job-related or
: server-related problems. There are many ways how global logs can be
: created. For example, you can setup jobs to write start/finish/error
: events to a centralized database using job notification actions. The
: drawback is you may need to install database client software on all
: servers and modify all jobs. Or you can periodically ship schedule.log
: files to a central server where you would then run command line job using
: HTMLGen.exe utility that comes with 24x7. This utility can produce global
: HTML log files listing job events for all servers.