I disagree with the strategic bombing part - proof is here
https://forums.civfanatics.com/threads/real-strategy.640452/page-4#post-15338899
As for Nukes - as I wrote in AI thread - each operation is a separate one. Same for "Nuclear Assault". It may very well happen that AI will nuke other cities that it is actually trying to capture. That is what I observed - there was no attack, just nuke after nuke.
As usual, I suspect the culprit is BH node "Operation Change Target". The purpose of it is: "As part of an operation, if you can't take the current target, find a new one or give up." As you can clearly see - the condition is NOT fulfilled because after nuking you CAN take a city (after thermo there is nothing stopping you around). So, there is no need to change the target and AI will nuke it until it is captured. And since it doesn't want to... well... the result is obvious.
I will make some tests during the weekend to see if removing that node from the tree will change things. The tree should finish and after restart select a new target from the stratch.