Hi. I have those on my Philo Autumn (1 in the first below photo...top arrow). Based on where the new shoots are on mine, my take is that it is a shoot. Here's my reasoning: All the roots on mine, which has 2 stems, come out from just below the segment joints. All the shoots come out from just above the segment joints.

In late winter I started watering slightly more, misting more, and giving it more light. After that began I noticed the new shoots. I never thought to conclusively track the scale-like protrusions to see what happens to them. I will now though.

The cut leaf shown below was done to allow more light on the shoots. There are also some more shoots that are not shown:

New green leaf shoot in an area where mostly roots are (bottom left):

The horn that never changed in almost a year. I noticed it during a time that I didn't realize I could safely water it a little more:

Thanks for sharing your knowledge on this! After some more digging I’ve read up on Axillary Buds and I’m thinking that’s exactly what these are; they’re the new shoots found in the axil of the leaf!