I don't think you're just making shit up, I can't think of a reason why you would.
but I do find it very unlikely that the hollow stem would be filled with fluid. never seen it myself(have seen hollow stems, but not with fluid), and I see no reason why it would be there. it also doesn't fit with other plants with hollow stems, which are all filled with air(as far as I know).
and if all those hollow stems were filled with fluid, it would also make all those hollow branches pretty heavy.
so nothing against you, but such a claim just goes against everything I know, and we're on the internet, so I'll be skeptical unless I see a picture.
I really don't want to imply anything about you personally, it's just that in my time on the internet I've learned to never trust anyone on their word alone.
I'm thinking possibly you did see fluid coming out, but it was actually coming out of the solid part of the stem(from the xylem), and you thought it was coming from the hole?