My guess is that you can take the RV to a dealership, and have it checked out. Any service should be a minimum of 1/4 to 1 full hour at the shop rate, usually in the $75 per hour to $120 per hour.
Or you can buy a new propane regulator, replace it yourself in about 15 minutes, turn on the propane, spray on a little soapy water to check for leaks, and pat yourself on the back for a job well done. Cost of parts is only going to be about $35.
Some say to replace the regulator about every 10 years or so, because the internal rubber seals can start to leak over time.
Some regulators can be adjusted, but the cost might be 1/2 to 1 full hour of shop time, and replacement (if you can do it yourself) will be less expensive. And the shop might tell you to drop off the RV, then they will have a tech look at it, they will write a report, then call you with a estimate - 1 hour to install a new regulator, and cost is $75.65 (yes they mark up the price from what they paid for the parts) and another 1/2 hour that the tech spent diagnosing the problem and writing up that estimate. For a grand total well above $150.
Fred.