Neeeeeeeeever happening in my game. Nope, nope, nope - saw it on YouTube and it broke my heart.
Though I don't know why ANYONE who encouraged him to stay loyal to the Qun is surprised when he stays loyal to the Qun.
Saving the dreadnought isn't really encouraging him to stay loyal to the Qun. It can be simply seen as acting in the interests of the Inquisition. Or you can even make a moral case based on the likely crew size of the dreadnought, or the duty you have towards your allies.
What it is, however, is putting the (supposed) greater good over loyalty to your friends. So it's hard to criticise Bull for not valuing your friendship highly enough to betray his people and faith.