Glad to hear you found the culprit! Ammo makes a big difference, as well as Cleaning and definitely taking apart and Cleaning the Mag. I very lightly oil my Mag Spring, as well as the interior of my Mag.
I've got 395 Rounds in my BT380, and have never had an FTL/FTF/FTE. I've used a wide variety of Ammo Brands, and it'll eat whatever I feed it.
Hopefully, you'll be back in the swing of things, on your next Range Trip!
Best of Luck!