I bought this fire bowl based on the fact that this was sold as something I can "convert to natural gas with the included conversion kit". I had a certified gas professional make the conversion, but afterward I noticed in the owner's manual that it has a warning that says, "WARNING: This outdoor fire bowl is for use with liquid propane gas only. The conversion to or attempted use of natural gas in this outdoor fire bowl is dangerous and could result in serious personal injury or property damage". So, am I at some sort of risk? Why the discrepancy?