That's normal operation, mine work the same way.

AC systems work better (maintaining comfort levels and removing humidity) and last longer with fewer cycles in number, of longer duration. I don't know if this function is done by thermostat or the control equipment, but it doesn't matter. If you were to change the setting of your thermostat to 74 degrees the instant it reaches a set temperature of 72, you'll find the temperature will increase to 73 in a matter of minutes and if you turn it back to 72, it will restart in a few minutes. It continues to run at 72, when that's the setting, to avoid that.

Your home continues to absorb heat from outside whether or not the AC is in an on cycle and prolonging each cycle is done to reduce having more frequent on/off/on changes. If it continued to run and produce a temperature a few degrees below the setting, then something is wrong.

I don't believe capacitors have anything at all to do with ending a run cycle. That's done by the control system cutting off the electricity needed for the components to run.

As stated already, there is nothing wrong with your AC, it's normal operation.

Thermostats, depending on the design parameters, typically swing the room temperature between 0.5°F to 1°F above and below the setpoint to maintain the setpoint as an average. The room temp display reads in 1°F increments so it may show 72°F when the room temp really is 72.5°F but the system doesn't shut off until it reaches 71.5°F per the sensor. The thermostat also is somewhat affected by the temperature of the wall on which it's mounted, and the mass of the wall doesn't respond to temperature changes as quickly as the air. Perhaps try setting at 73°F instead of 72°F ... you may still be comfortable.