Noticed an episode listed last week, but it was the premiere which had already been offered. I assumed it was merely a bit of "reflux" for the YouTube algorithm. A day or two later I saw another one listed. I went to the Paramount+ channel of YT to investigate and discovered all ten episodes of the first season were available!
Having already seen the premiere when it was first offered, I started with episodes 2 and 3 Monday night and 4 and 5 last night. I hope to finish by or during the weekend.
Now, I have not seen any official statement to support this, but I suspect this is some kind of "limited engagement", offering the first season for free until (or maybe just after) the premiere of the second season on the streaming service. After that point, the episodes will be "pulled". If people want more (specifically, the new season), they will have to subscribe to the P+ streaming service. Actually, that's smart if mercurial strategy, kind of the "dealer" approach.
Anyway, it's been a trip finally getting to see these episodes, discovering all the Easter eggs provided, some obvious, like the "Amok Time" fight music, others more obscure, like the recorder buoy "Bleep!" from the second pilot used as a kind of radar return "blip" in the fourth episode. I still have 5 episodes to go, so circumstances may change reactions later, but it's wild to see T'Pring in a sympathetic light when for more than 50 years, fans have seen her only as dastardly manipulative!