If you have multiple lifegain triggers and are just under 27 life, you want the non-Valkyrie ones like [[Bishop of Wings]] to resolve first, to gain the toughness boost (from the Valkyrie's other ability) and gain 2 extra.
Arena always orders the triggers so that any Valkyries resolve first. Other cards and interactions in the past have received custom overrides in the rules engine to make sure they occur logically.
At the moment I have to remember to go into Options and turn off auto trigger ordering just before this situation, then turn it back on again because the deck spams a LOT of triggers. (Except, curiously, in the one game I played after updating today, where it appeared to stack the triggers 'correctly').