Hello Jobi:
I've seen both active and cryptic Acanthosaura though I agree with you about liking active animals more. Even my new male, "Ing-Ba," watches for me to open the lid and he's there for a handout.
It's possible that some regional micro habitat activity might be at play here. It sure would be interesting to get lots of field notes on these guys.
By the way, I like the nice golden hue of the animal in the picture. A good lookig Acanthosaura for sure. "Ing-Ba" has a bit of gold flecking on him as well but not to that degree.
Have a Great Day!!!