I have a similar issue.
I have a task, which after upgrading to 5.5.3 (from 5.4.9) doesn't properly update the last run time for a single task in a job with 15 tasks. The others tasks act normally and display correct values.
The weird task just updates a user variable.
I can run the single task ok, I mean, the user variable is correctly updated, but the last run time just doesn't update for this single task. It is correctly updated for the job.
The log also confirms that the task was run:
25-02-2010 15:22:22 Info Variable 'OptagelseSendTeleadresse' was updated to: {REGEX(Replace|{TASK(2ef3fe56-7b8b-406c-a409-4d2bbe703d01,StdOut)}|\s+|)}
25-02-2010 15:22:22 Info Task completed: Sætter mobil nummer i variabel OptagelseSendTeleadresse (1867)
25-02-2010 15:22:22 Info Job completed: Optagelsesblanket - Email eller SMS
25-02-2010 15:22:34 Debug Saving Jobs
I have no idea how to substantiate this further. If you need some logs, please let me know.
Best regards,
René