Yes, there were two bombs as the plane broke. One bomb, from its internal perspective, had a "fully normal drop": there was the switch that was triggered only once the bomb actually leaves the plane through the expected door -- it was activated as the plane broke exactly in a way that from the bomb perspective it simply wasn't an accident but "do it." On that bomb, the only switch that wasn't "on" was the one which a crew member was supposed to pull prior to the drop.
On the another bomb, from which point of view the dropping sequence was less "normal" (the breakup of the plane made less clear-cut case from the perspective of that one, so some internal components didn't activate) the same switch was discovered in the "on" position.
So it was really, really close call.
(A "small" curiosity: These bombs are two-stage bombs, one weaker nuclear explosion forces the next, one stronger. The "weaker one" part of one of the bombs, with its radioactive content that has enough material for a nuclear explosion is still there(!) deep in the ground.)
On the another bomb, from which point of view the dropping sequence was less "normal" (the breakup of the plane made less clear-cut case from the perspective of that one, so some internal components didn't activate) the same switch was discovered in the "on" position.
So it was really, really close call.
(A "small" curiosity: These bombs are two-stage bombs, one weaker nuclear explosion forces the next, one stronger. The "weaker one" part of one of the bombs, with its radioactive content that has enough material for a nuclear explosion is still there(!) deep in the ground.)