With 6.1.3 I tried to recreate my issue and I wasn't able to recreate my issue.
I made three jobs which had three file write tasks in there in a loop (100 itterations). All writing to the same file.
I had an other job with a file change trigger on this file, writing also data in the file with the file write task (this is an infinitive loop..)
The last job was running the first three jobs at the same time.
When all the looped jobs stopped, I stopped the triggered job manualy.
The only issue I encountered (once) was a file in use error within a loop and the whole job stopped.
All the lines were there in the file. So it's not a good recreation of my issue...
regards
Erik
Uses Visualcron since 2006.