I've noticed that too. Been playing through a sex-scene and had a dejavu moment. Looked to be the exact same art with the only difference being the background like you said. That is actually quite disappointing, especially considering this is drawn by hand, not like she's gotta use some DAZ presets. The possibilities are basically endless, so that could actually be called lazy.
It's not about the same position, it's literally re-used art from previous episodes. That's just not....cool. Not like ORS had all kinds of crazy sex scenes yet, and this has never been an issue in GGGB either from what I can remember.