Theoretically, absolutely. A valid OWP is legal status to live and work in Canada. However, the OWP does state that readmission is not guaranteed, as IRCC issues the work permits, and the CBSA controls all borders, and consequently, admissions. Visa exempt foreign nationals even get issued an eTA to facilitate readmission too, so it’s clear that IRCC has no issues with people coming and going.
It boils down to that IRCC can’t control the actions of individual CBSA officers. Their role gives them absolute autonomy in decision making to allow someone admission into Canada. Hence, IRCC can’t guarantee you’ll be given readmission.
That said, despite the warning that readmission isn’t guaranteed, I don’t think anyone on here has had any issues traveling with an OWP. Short visits outside of Canada shouldn’t be an issue at all. I can’t think why the CBSA would deny someone entry just for taking a short trip, after all, you have an OWP, you have legal status. I don’t think they’re looking for reasons to deny someone entry. The warning seems to be as a result of the fact that only PR holders and citizens have right of admission.