Usually due to battery level being low. It self protects itself by disabling many features that would require battery usage such as communicating remotely with the vehicle. Can you check to see if your battery is reading low? Perhaps take it in to an auto store or shop that will hook it up to a battery/load tester for you.
My remote start from the app seems to automatically choose to warm or cool the car
This is accurate if you leave the settings to "Auto" in the truck and allow it to maintain/get to a set temperature all on its own. If you have your heating/cooling set to anything manual in the truck, it will stick with that manual setting when remote starting (ignoring the outside temperature). Blasting the AC when you last drove it at 2 PM when it was 85 degrees out via the 'MAX AC" button? Gonna blast the AC when you remote start it at 4 AM the next morning when it is only 60 degrees outside. Same for heating. Setting heat to max in the truck is going to blast the heat when you remote start it, even if it is already warm/hot in your truck.
