The sentence you quoted seems ambiguous to me, since (from what I understood reading the article) there are two separate storage mechanisms using the new featur

The sentence you quoted seems ambiguous to me, since (from what I understood reading the article) there are two separate storage mechanisms using the new feature. The two possible beliefs the engineer may have had are: 1. Since we tested the change on a subset of A for a few weeks, we can assume it will work for all of A. 2. Since we tested the change on a subset of A for a few weeks, we can assume it will work for all of A and all of B. #1 seems reasonable, but #2 is what needed to hold true in order for there to be no problems, since the change was actually enabled for all of A and B. But was the engineer actually advocating to enable the change in B, or was that an accident during the manual deployment?