Confusion about a gamerule

I have a gamerule that decides whether or not one of the bosses i've made play their boss muisc. And for some reason the things actting werid and when i used a print block to see what going on i got this

I have no idea what could possibly be causing this. Or why the Server thread that should be handling it is giving me the right result.
And the Render thread that from the name alone shouldn't be bothering with gamerules is saying it is. Or why the boss is using that as it's value. Can someone please explain WTF is even somewhat causing this