Bridge bombing bug?

[Etude]

I played a game recently where I attacked a bridge with strategic bombers. I got some strange , even nonsensical results. The after battle report said things like '867 vs Bridge 750. Bridge has survived'

How can the bridge survive if I have inflicted more damage points to it that it had at the start?

This was no one off. I repeatedly got this kind of thing. Furthermore if you don't destroy a bridge on the first bombing run, it often seems pointless to continue attacking, you can keep piling on more and more bombers, enough to theoretically destroy the bridge up to about twice over. but the after battle report always says the bridge survived.

Is there anyway of seeing damage details to bridges? It' s easy with cities, you just click the hex and it tells you how much damage.