I'm not sure I'd call this a "bug" although it is an interesting "use case," not one we'd considered. I'd say that "normally" we'd expect the power up chart to start the other charts and then that other "looping" chart would make sure the comm handle was opened and STAYED open.
But who's to say what's "normal." Initializing other (non-comm handle) variables is pretty normal to do in the Powerup Chart. Also, is see we're talking RS232 comm handle here (I'm hoping this is using a built-in port, vs. a remote 232 module). A local 232 port comm handle would be less important to monitor for open-ness than say, a comm handle talking to some remote tcp device--we're your connection is likely to drop of any number of reasons.
I could also see how, if you were using this same comm handle in multiple charts, you might have just one of them (maybe even the Powerup chart) looping to check if that comm handle is still open, and log/email/turn on an alarm etc. if it's not--so the other charts don't have to all check.
In any case, thanks for generously sharing these good-to-know details!