Nice to see you here at the vtl Forum. Welcome aboard.
To solve the problem you're seeing, use the ActivityController to pause or outright STOP your collection activity. This allows the child process generated by the shell to send the collected data back to the vtl command. To learn a lot about that command fast, try this:
$ man ActivityController
(Note upper case A and C, one word)
Try this too: run a test vtl command, and, once it's started, go to a prompt and type:
That program will say it sees the running collector, and ask you to pick what you want to do from a small menu. Couldn't be easier.
If you're like me, you may run ActivityController while vtl isn't doing anything, just to see what happens. It actually says, hey, I can't see any activities to control, and returns a shell prompt.
If you use a reflexive CTRL-C to stop the collection (and to kill the shell that the collection process is working via), there's no opportunity for the data in RAM to get flushed back to the vtl command working files. CTRL-C just kills the shell, bammo. And you lose any data that was collected in RAM, waiting to be saved and seen.
If you use the ActivityController, I think you'll get exactly what you're looking for. Either way, report back here and let us all know.