I wouldn't obsess about her phrasing. I know it's hard but tenses are weird and she very well could've meant nothing by it.
I think keeping the cordial is a good plan since she's so edgy Don't ask her questions, don't respond to anything personal but answer straight forward, the same way you would to a neighbor. (Like if a neighbor asked about the dog, what would you say? "He's doing well")
M:26 H:32 T:8yrs ILYBNILWY/ "I'm not happy": 2/6/16 D-Day-discovered PA/EA: 2/10/16 Separated: 2/14/16 He's living with OW I moved to different state: 06/16 Currently: Trying to move forward