A Japanese comment on Twitter noted that Graf here isn't wearing her wedding ring, so this may have taken place before their marriage.
Apparently Ido just forgot
You can't fool me!You're smiling up a storm there, deesu.KONGOU!?On the schedule for today is Murasame's strengthening practice, a patrol of the Moray Sea...Give that to Nagato, yeah?Eh...By the way, what's with the maid getup?W-Well, I just felt like it, so...It's cute.You'd say that to anyone, wouldn't you!Admiral!
You really must take your work a little more seriously!