OH lord, isn't that just the grossest thing ever LOL
I've never had the problem, but have heard of a few suggestions:
1 - diet can be a factor, sometimes the dog is lacking something in it's diet and is looking elsewhere
2 - it definitely becomes a habit, and after a couple of successful "meals" will be much harder to break
3 - the pills that your vet said will make it less "tasty"? Really, like poop isn't gross enough? LMAO ... sorry, can't resist that one - there really isn't much that's absolutely disgusting to a dog ... seriously ... they'll eat any type of poop they see - deer, rabbit, goose, duck ... you name it, they'll eat it if given a chance! Ask the farmers on here ... cow poop seems to be a favourite, and they love to roll in it too!
4 - what are your feelings / actions about it around your dog. I watched a woman at an off leash park freak and run at her dog as he was trying to gobble some down and he thought it was a game ... almost like the poop was a toy, and he had to grab it before she got there ... are you calm about it? are you freaking out? (I get it, it's gross) but if you're providing drama / excitement the dog's get hyper too!
You need a SOLID leave it, and I mean SOLID ... so that the second the dog is done his business and turns around to investigate you say LEAVE IT ... and mean it ... not a pretty little "leave it" but a STERN leave it (you're not yelling, but you're using "that" voice.)
If you have to have a leash on the dog and be ready to tug away so that he's not rewarded for getting to it.
I'm sure others will have some ideas for you as well! Good luck!