invented to keep out the cold
"Ah, well, there's a reason I know about the plague. I was looking for a way to go back down, finish off my circle and be sure I knew what to spend my share on. I didn't want to dive in on my own, though, so I saw the guard asking for volunteers to talk to the otyughs and I thought oh, that sounds safe, the guard can hire clerics and has people with nice big metal armor on to hide behind. So back on the 4th, I went to the station to volunteer and ended up looking in the sewers. The next day, I came back, we went a bit farther, and what do you know, there were the Urgathoans dumping their fungus stuff straight into the sewer water. It did explain what the otyughs were complaining about, that's for sure. So I spent Fireday helping them breach the Urgathoan cult, yesterday I saw it in the papers, and you know the rest from there. It's been a busy week!"
She already told this to Anton and Julio in her letter, there's no point trying to hide it from Mika. Trying to maintain a lie like that when she's expecting more work from the Guard would also be far more effort than it's worth, even more so when she's so identifiable. Also she doesn't have any specific reason to conceal it, but a memory never really dies, by the time you know you need to hide something it's too late to start.