Was the plant outside.. If so then it might be sunburn? but strange that it only happened to those...and it looks more like they just went soggy....
The same thing happened to some of my cherry toms and I just wrote it off to sunburn.....
I did however, rip them off the tree and burn them with the ashes of an old priest, 3 hairs from a cat and an eye of newt, and the whole time chanting while holding a lite purple candle.......
Hmmmmmm, funny but I don't think i helped you out much.....
Thats a good sunburn where the mator isn't shade and gets exposed straight up with the sun. It happens but it should not hurt the plant just pull them off and wait for the next ones. I usually throw mine to the cows and they say mmmmmmmmm wheres the spice.
Whew - yeah it's supposed to be a disease resistant plant & I couldnt see any bugs. Wild though how it nuked half the tom.
Theres about another 30 green toms on the plant now that are fine but will ripen while I'm away