Hi all!

My 1 year old ficus lyrata was doing just fine a few days ago when I last looked at it. Today I happened to notice one of its top leaves started turning brown. The weird thing is that it's only this one leaf. I've searched high and low on the Internet for an answer since I've never seen it brown like this before (even its predecessor had the quintessential edges turning brown or turning yellow due to my overzealous watering). It almost looks like it's affecting the veins first and spreading out to the leaf surface.

My FLF is currently in a west facing window where it gets a nice amount of indirect sunlight for a few hours every day.

I have three suspicions:

#1: Underwatering? I was out of town for 3 weeks on vacation so I haven't really watered it in over a month, save a few random splashes of water I had lying around from unfinished drinks.

#2: Lamp burn? I noticed this leaf sits under a fluorescent lamp, which is only on for a few hours every evening. Could the light be burning it?

#3: Wind burn? I've been running my wall heater since it's been especially cold here in Southern California. The FLF sits under the AC unit, but isn't directly in the path of air flow.

Any insights? The rest of the plant looks otherwise happy and healthy. Please help!