Star Trek: 10 Secrets Of The USS Shenzhou You Need To Know
4. Good Shepard
As the first year of Star Trek: Discovery developed in the writers room, the producers alerted the art department that yet another Federation starship (other than the Discovery, Shenzhou, and fleet) would be appearing later in the season. This ship, the USS Curie, was intended to be another experimental starship and so a unique vessel was devised by John Eaves.
Returning to early sketches of the USS Shenzhou, Eaves flipped starship upside down, placing the bridge back on the top of the saucer and the engines above the primary hull:
The basic lines were a rejected Shenzhou, but I reworked it to be the Curie.
Bridging the gap between the older Shenzhou and the brand new Discovery, Eaves tied the two ships together to create the Shepard-class USS Curie... which would later be renamed Kerala and then dropped from the show entirely. Deciding the experimental starship should be the same class as the Discovery herself, the writers instead settled on the Crossfield-class USS Glenn, which would appear in the series' third episode "Context is For Kings".
The Curie aka the Kerala would go on to appear in "Battle at the Binary Stars" and later stand in for the USS Gagarin in "Si Vis Pacem, Para Bellum", so no, you weren't just seeing an upside down Shenzhou in those episodes, but close.