Is this a parasite bore hole? Found it towards the bottom of the plant
No, you’re alright. Totally normal…
Lol! The stems are hollow
That’s how they get the water to the top. 
Ur all good. 
The stem is hollow which allows the water to be drawn up easily. You are good. I took a old main stem of my GSC on Steroids and it was hollow.
Normal. Like bamboo.
Some stems are solid all the way through. Hollow ones are normal too though.