Yes, kind of. Or going back. I am really digging the flats on more basses. I play bass, rarely slap or pop, dont' seek to cut through anything so flats often give me that big thick bottom with some punch that I like. And once you put falts on and love the tone, you're kind of done with strings for at least a decade on that bass. Added bonus. That and I've tried enough strings now that I know what I like and chasing strings is of less interest. Especually when I'm really satisfied with what I'm hearing. Nothing to chase at that point, just play and enjoy.
I've had flats on various basses for years. It's been >20 yrs since I was all rounds. Several years ago most basses had flats. But I had fewer basses as well. But the number of basses that have flats has been creeping higher again. Most of my Pbasses have always had flats. The '55 mostly rounds. (Some flats don't like string through, and the SIT Powerwounds sound great via the ABM.) The Cal Sunset Orange Fender P/J has never had rounds. Used GHS Pressurewounds for years. It currently has Roto flats and they sound great on it. Both J's have flats--'63 DTFs and the '71 Rotos.
One VP has rounds, the other GHS flats. The '76 and '64 Embassy Roto 66s. Black nylon's on the '06. The new Embassy "donor" bass has Stringjoy rounds and the '21 NR DM Blue Steels and does the Regenerate (the modern take on a '55 Pbass). The Redburst G&L has SIT Foundations.