I have a 2004 J-385. A bit different, but the same general age.
Your understanding of Standard/Economy matches mine - it shouldn't turn on to heat the water except during the programmed cycles when it's in Economy mode. That's how mine works. In Standard mode, anytime the water temperature drops, pump 1 will turn on to heat the water.
The Circulation pump is programmed separately. It doesn't pay attention to the Standard/Economy setting, and it Doesn't run the heater. It's whole purpose is simply to circulate the water, especially if you have an ozonator on the Jacuzzi. If a lot of people use the Jacuzzi and you have an Ozonator, Jacuzzi recommends that you just set it to run 24 hours a day. If you don't have an ozonator (or the ozonator is dead), you can probably set it to not run at all and it won't affect the water quality.
So, I think the Jacuzzi is operating normally - pump 1 came on at 6:00 PM and ran for 30 minutes, heating the water, then it turned off. The Circulation pump also came on at 6:00PM, and ran until 9:00 PM because you have it programmed to run for three hours. When you came out at 8:15, you saw the circ pump running and the water was hot from the 6:00-6:30 cycle.