Orchid potting mix has micro organisms, fungi, bacteria so the idea that it should be sterile is not correct.

In fact, many of the beautiful Australian Native Terrestrial orchids need beneficial fungi to survive.

How long has the plant been in the mix and is the plant thriving?

If you are worried, do a repot into new mix.

Purchased the orchid about 2 or 3 months ago, and the mix is original. Was waiting to repot until after blooms had faded.

About 3 weeks ago I noticed sap under the leaves, which I believe was just “happy sap”. Since then, I wipe the leaves weekly to prevent any sap build up. Otherwise, plant has appeared pretty healthy.

I have a few paphs that are potted in more organic media than my other orchids, and every now and then get a tiny 'shroom pop out of the top or bottom. It could be an indication of your media breaking down, but they are otherwise pretty harmless. As you can tell through the pot, your orchid is doing quite well! If you see the roots taking a turn for the worse, I'd dump that media, but in my opinion that's not yet necessary.