2014 Civic has a starting issue, 88,xxx miles. Battery & alternator checked out as good. Belt is tight, battery cables tight on terminals. No excessive corrosion on battery terminals. This issues has happened 3 times over the last month, so I'd call it intermittent. All 3 times I was sitting in a parking lot with the engine idling for 10 - 20 minutes with no signs of a problem, car running as it should, then shut off the car. Tried to start the engine after sitting for about 5 - 10 minutes, so the engine was still warm, engine would not turn over. All 3 times I jump started the battery. Engine started right up with a jump. Does not appear to be a fuel issue. Car does not have a push button ignition. I have had no other issues with this car. Any ideas as to what my gremlin is?
I would check the connections as suggested, but more importantly: do a "voltage drop test" across the major battery cables, including ground, while the vehicle is running and hot. Or better yet with the help of a friend, while cranking the starter.
I suspect you may have cable(s) that are corroded internally (not visible).
This manifests itself as the symptoms you described. As the temperature goes up, so does the resistance.
The Temperature Coefficient of Copper (near room temperature) is +0.393 percent per degree C. This means if the temperature increases 1°C, the resistance will increase 0.393%. ... The wire resistance will now be 1.015 ohms + 0.0399 ohms = 1.0549 ohms.
Keep in mind that only a few additional ohms resistance can cripple the current flow. Any battery cable showing more than a few tenths of a voltage drop should be replaced.