Thank you for your insight Camille! It's a pretty new purchase, I've had it for only two weeks and as you can see from the photo, it suffered a bit of mechanical damage from the packaging so I don't know if that could've contributed to this as well.
We also had a crazy storm yesterday and rain water could've splashed on to it without my knowing. Today, however, was a very bright and sunny day and even though my orchids are in a pretty sheltered east-facing spot with indirect light most of the time, they do get a tiny bit of direct sunlight for about an hour or so. With all these possibilities, I'm finding it hard to pinpoint the exact cause.
I'll try moving my orchids to a safer spot in the meantime just in case it is sunburn.
I'll definitely use the 'wait and see' approach the next time. I was just so scared of the whole plant being infected that the scissors immediately came out.
Thanks again for all your help!