I think Natasha might have found out that Ashe is a Duplo through her forgotten underwear, because she's a pervert and sniffed them.

Through her job has access to Ashe's phone number. While she has all the tools to send that text at the end of the update, others in the thread have pointed out that it does not fit with her character and I no longer believe that she is the one to have sent that text.
Moira is a good guess, in her quality of mayor she has connection pretty much where ever she wants in the city and she did say that she had more interest in her than in any other of Vanessa's one night girlfriend. she even offered our MC a job. Now what would be her motivation to send that text? To try and keep her away from Vanessa or to blackmail her.
Motivation is something else we have to think about to pierce this mystery. Hate and prejudice would be enough for most people of low standard, but up to this point in the story I am not convinced we have met someone so low.
Jessica, While hostile, really, toward everyone does not strike me as someone who would waste her time doing that in the middle of the night. The only motivation she would have is vengeance toward Vanessa and with the reputation for Vanessa having always a different girlfriend that does not seams like the right way to get to her. Jessica's character remind me of an other that I have read about in a comic. If it is the inspiration for her and Moira, there is more to Jessica than a simple bimbo.
An other option I would like to propose is the street drug dealer which name I don't remember. When Ashe call her regular dealer the discussion can lead the reader to , maybe falsely, assume that she is a duplo as well. That street dealer know who sent Ashe to her, she can pull an easy conclusion from that or at least try an easy shot in the dark that has no cost to her if it miss. Also geting Ashe's phone number if she does not have it already, can't remember, would not be hard. Her motivations could be multiple, with her line of work they are not difficult to imagine.
The more the story develop the more Eruption Imminent is looking like a title that refer to more than a money shot even if Jessica did pull one on us this episode.