Have you noticed whether the intensity shift happens on certain days of the week, or after specific activities like showering or exercising?
The thing is, perfume performance genuinely does fluctuate based on your skin's state at any given moment. Humidity, body temperature, diet, hydration levels, and even your stress hormones all affect how volatile the fragrance compounds are and how well they project. Black Orchid in particular has a pretty heavy base, so on days when your skin is slightly more acidic or your body temp runs cooler, it'll cling closer to your skin instead of diffusing into the air. You might think it's weaker when really it's just sitting differently on you.
The other factor worth considering is that your olfactory system habituates to familiar scents ridiculously fast - way faster than you'd expect. So even if the perfume is performing identically every day, your nose might just be tuning it out on certain occasions while someone standing next to you would say it smells perfectly normal. If other people occasionally comment that you smell great without you even noticing it, that's a pretty good sign your bottle is working fine and your nose is just doing its job a bit too well. A year in is way too soon for the fragrance itself to have degraded if you're storing it away from direct sunlight.