Occlussion culling or invisi-prims broken/fixed?

Just noticed this after getting into 1.9.1(25), basically my FPS is now right back to main-grid level, all the wonderful speed improvements 1.9.1 heralded for me with the first preview have left me

Basically, if you go to my occlussion culling (invisi-prim inside) box at Morris 89, 217, 73, then you will find that not a single objects seems to be getting culled any more. Ordinarily for me most of morris would be culled along with a lot of flex-prims (though they'd sometimes take a while to disappear), this is no longer the case. SL is now rendering EVERYTHING, even though culling is definitely switched on.
This is odd, because normally I'd enjoy a nice 35fps inside the box, I'm now down at 16fps.

It's difficult to confirm this properly, but there is no noticeable difference inside the box than outside, same goes for creating an identical box with opaque insides. FPS inside is same as out, where before it would be around double the framerate in the box.

So I'm posting to see if anyone else has noticed a similar apparent fault with occlussion culling in this version?

This is on the Mac Client at least, dunno if others are affected or not.

Yeah I thought it was wierd how things didn't seem to be culled, wasn't sure if it was a simple matter of a new way the octree shows culling or whether its borked. I think its probly borked.

There is indeed a bug in the Occlusion Culling system in 1.9.1.25. It will be fixed in 1.9.1.26, due out by mid-day Monday May 15.

1.9.1.25's OC fluctuates between 'it culls absolutely nothing' and 'it looks like it works better than ever'. Mostly the former, however many opaque buildings you try to hide your camera behind. Then suddenly after a bit of luck and winding the camera in and out on-the-spot, IN COMES THE RED and it looks more comprehensive than ever.

I look forward to 1.9.1.26 and hopefully more of the great latter behaviour!

As do I, though I admit I haven't been all that successful getting it to show up.