It's possible the website doesn't update the last active date instantly. She might be using the Android app with push notifications on, saw you favorited her, and did the same to you. Maybe check her last active status in 24 hours?

It's been my experience that the TGTBT impossibly attractive ones [9-10 on the level of a supermodel] rarely if ever pan out. These are almost all pics posted by scammers to rope a dope. But I still cast a line in their direction in the once-in-a-lifetime chance they turn out to be a unicorn. If they are for real, though, chances are they are holding out for a whale for such beauties command top dollar.  

I think you're on the right track.  Would it surprise anyone to find out that the TGTBT profiles are phonies, set up by SA to give potential SDs hope that there are bigger fish out there?

Just speculating that there might be privacy settings that SB's can select to hide activity, etc.  Not sure, of course.
.
It would be odd to build bots on site that don't mimic human activity.  But I suppose lazy programming could account for that.
.
It is always a mystery how many bots are on these systems.  Having been on a site for several years now, I do recognize some SB's who are there everyday for years.  But also I have met three or four of them for BCD, so obviously not bots, just working girls, so to speak.

This happened on 7/28/24:  

Her "Member Since" date was 7/27/24
Her "Active" was 4 days ago.  

 
So how was she active 3 days before she was a member?  

 
I have seen new (e.g: they are at the top of my "Newest" sort results) profiles appear after profile that I saw the previous day.  

Example:  
On Monday - I see profile 1 then 2, and then 3 as "newest"
On Tuesday - I see profile 1 then 2, and then 4 followed by 3 as "newest"

The create date for profile 4 is after the date for 1, 2 and 3. But it sorts before 1 and 2.

Speculation: Some profiles may be delayed in posting/appearing by one or more days because Seeking has not approved them yet.  That could explain a profile created on Monday (or before) not showing up until Tuesday, but it has Monday as the create date.  

 
Final thought: There is a setting to have Seeking send a notice email to a user if certain events happen, like getting favorited. I don't use it.  But that could explain why Papa's favorite of a 2-month dormant profile got him an instant reply.  On my "research" profile I have this option shut off due to the high number of email notices "she" was getting - up to 60 a week when the profile was recently active.  

 
Conclusion: Not too worried about it. Perhaps it adds a light-yellow flag when my Spidey Senses are triggered by other red flags. But  

 
Life is good

 
The Cat