Fungus/not fungus opinon

OK, so not an EF lens, but I just bought this FD 35-70 f4. Optics and everything seems fine, but there are markings/something on one of the inside elements.

Looking through pics, I have not seen anything that looks like this. The glass is really clean, so I'm wondering if someone cleaned it and did something, but it doesn't look like scratches either, although there is what looks like a circular abrasion under it.

If I like the lens, I may just buy another copy, just in case, but wondering if anyone has seen anything that looks like this before.

Thanks.

Not fungus. Some dingus was working inside the lens and left a partial fingerprint.

I concur, does not look like fungus but a fingerprint.

Thanks. That was one of my thoughts, it just seemed a bit too opaque for a finger print. But in any case, good to know it doesn't look like any fungus you have seen.

In all likelihood, they picked up helicoid grease on their fingers and that's what left such a heavy fingerprint.