Here's a close up of the stem.

Seems like a fertilizer salt build up. You can wash your plants under the tepid water and leach the soil until the runoff looks transparent.

After that - put your AV on a stack of newspapers in a warm dark area and cover it with a paper towel until it dries. Cold air or bright light can spot wet leaves.

Healthy looking plant!

Irina

Thanks Irina! The second pic doesn't show it well, but the stem is actually half 'eaten away' where this buildup is. Maybe the salts are acidic enough to eat into the tissue where they accumulate? The leaves are still turgid despite the deformation. I really hope that that's all it is, but if anyone else has other thoughts, I'm happy to consider them. I am a bit of a newbie.

I think the salts attract water - and dessicate the tissue - that's where the lesions come from. It is more typical when growers use clay pots which get saturated with salt quite soon - and similar lesions appear where the leaf touches the rim of the pot - that's why plastic pots are better.

If you investigate on "petiole rot" - you will find more.

I.