Shooting a propane tank, except under very rare circumstances, would not cause it to explode, this is a very common TV/movie mistake. In order for the propane tank to explode the gas inside would need to be ignited, like by a spark. Almost all bullets are made of a lead core and a copper jacket, including the bullets used by law enforcement. Neither of these metals make sparks when hitting other metal, in fact a lot of target shooters like to use empty (or nearly empty) propane tanks for target practice, because puncturing them with a bullet causes the propane to rapidly vaporize, sending the canister flying up into the air, but it does not "blow up". About the only kind of bullet that could make sparks would be a steel core armor piercing bullet, which is only used by the military, they are illegal for civilians to own and use, and it is not the type of bullet a federal agent would have in their sidearm.
The house that Agent's Boone and Tara enter to do a "wellness check" clearly has the deadbolt on the front door locked, yet Boone kicks the door open with barely any force at all. This is a newer home with a solid looking door, with the deadbolt locked it would take several hard kicks to break it down. Sometimes even battering rams need a few hits to knock in a deadbolted door.
In the undercover scene involving the Russian arms dealer, the deal happens in Kailua-Kona, which is on another island. The team gets there and goes back to HQ seemingly on the same day without mentioning flying between the islands, which is odd considering the circumstances.
As the two agents approach the missing pick-up truck, one comments that it's in a remote location, "a long way from the port". In the long-shot of the parking area, the loading cranes from the port can be seen about a kilometer behind them.