str.split() with no argument splits on any run of whitespace and strips trailing spaces. This means that if there's no hostname in the output from squeue, e.g. for a pending job, split produces 3 values and then unpacking fails (silently). The job monitor then falls back to calling sacct, but new jobs may not be in the accounting database yet, so it gets treated as a finished & failed job.
Splitting on a space explicitly preserves the hostname field as an empty string.
With a value from the logs, after the log call was hotfixed in.
In [1]: '11846333 PENDING 0:00 '.split()
Out[1]: ['11846333', 'PENDING', '0:00']
In [2]: '11846333 PENDING 0:00 '.split(' ')
Out[2]: ['11846333', 'PENDING', '0:00', '']