I've heard the JD says to rest LP9 for 6-12 months and definitely not more than 12-18. If you smoke it before the 6 month mark you will get the ammonia odor and taste that you spoke of. I got one early on in my smoking career and it just reeked of ammonia, but within about 4-6 months the odor has dissipated. I smoked it at almost exactly the 12 month mark and I have to say... it was amazing. It was definitely strong, but the flavors and complexity were incredible. I never thought about what my next smoke was while smoking the LP9 and was sad when it got too hot to hold.

Additionally, I waited almost exactly 12 months on my first T52 and the results were the same. I think you have to make sure you hit around the mark JD claims for it to be the smoke he intended it to be.