Mip map problem

This is better picture:

http://img441.imageshack.us/f/xrengine201009181438057.jpg/

It happens when i choose "generate mip maps" option.

My best bet is that when mipmapped, the 0 bit becomes a 1 too easily, which results in transparent pixels providing color, but I am surprised NV is so dumb to do that... although it could really have no other choice in some cases.

Only with Point filter type this doesn't happen.

It's a common problem with alpha and mip maps. The differing alpha values are too close together and as you mip down the chain you're losing the mip values since it's only a single bit. You could custom author your mip chain though to get around the problem, or don't generate any mips for alpha, but that's less than ideal for texture cache performance.

So you are suggesting that i should create new script that scales mip maps?