TMZ has confirmed that the pop star and the NFL stud stopped by Madonna and Guy Oseary's Oscars exclusive after-party at a private residence in the Hollywood Hills on Sunday evening ... where there weren't any photos allowed inside.

Of course, British Vogue published a bunch of shots of stars who showed up and posed at what appears to be a designated photo-op area -- which had a bunch of fun cutouts, etc.

Some of the stars who were pictured included Robert De Niro, Matthew McConaughey, Jodie Turner-Smith, Lenny Kravitz, Salma Hayek and others. Notably, Taylor and Travis were not part of the photo lineup ... but are listed among the celeb guests who crashed it.

Like we said, sources with direct knowledge tell us they were in fact there ... even though they seem to have gone out of their way to not be seen/photographed, which is interesting.

Taylor and Travis landing here in L.A. comes after T-Swift's six sold-old shows in Singapore as part of her "Eras" tour -- which wrapped up this past weekend. Sounds like they were ready to get the hell out of there and come back stateside ... which is exactly what they did.

They enjoyed some alone time in Asia for the brief period Travis was there -- but obviously with her tour being on pause for a good month or so ... they were ready to come home.

They've had no problem letting their love story play out in the public eye in some settings ... but in others, they're weirdly private, and it really doesn't make much sense.

Remember, the singer supported the Kansas City Chiefs tight end at several of his football games -- including the Super Bowl -- and Travis has seen Taylor's "Eras" tour in four different cities. On its face, it seems like they're only cool being snapped in public at certain times.

Taylor herself even seems to be incredibly averse to being photographed at times -- going so far as to hidey under umbrellas to keep paparazzi from snapping her ... which, again, is so bizarre. Here for this after-party, it looks to have been more of the same ... ultra privacy.

Perhaps Taylor and Travis have had enough of the Dads, Brads and Chads weighing in on their every move? Time will tell!