Sponsors who are PRs are expected to remain in Canada, 'short visits abroad' are okay. No definition of short provided; a month probably won't cause issues but wouldn't recommend longer.
For inland applicants: if you have a valid visa and no other issues, you will probably be let in with no issues. But if you're not, that's your problem, and they may deem your application 'abandoned.'
Note that you really should have chosen outland; a requirement of inland is that the sponsor and applicant reside to Canada and will continue to do so throughout the process. Will they catch this and make a big deal of it? Probably not. But they might delay it and wait and see whether you both return (delays your problem, no guarantee the delay will only be a month - they could put a note "check it in X months" and even then not get to it).
And of course - this isn't me making some moral judgment about it (I don't care), just noting the reality that this is not clearly explained in the inland/outland docs when applying, and it creates potentially harmful uncertainty.