Thanks for the reply. Yes, the log files are all stored on a network. I had thought about changing that to a local file and then copying that to the network folder, as you suggest, but that's a LOT of stuff I'd need to change. Some jobs create a brand new log file for each run, others write to the same log file and just keep accumulating (the files are archived once a week). It's possible I could create a new job with a VisualCron trigger "on job completion", and have it copy the previous job's log file over to the network location, which would avoid having to add the copy file task to every job I have. But the issue with writing the log files locally is that I wouldn't be able to view the log file as it's being created, unless I remote desktop into the virtual machine that we have VisualCron running on.
Also, these network log files have been working perfectly from when we first implemented VisualCron I think back in 2018 up until only a month or so ago. I agree though that since we haven't made any changes to our VC config (or version) recently, the likely cause would be network issues, so I'll have to go through the jobs and alter how they log stuff to see if that fixes it.