Temporary Mana is lost when gaining new crystals from Nourish

[Jetz72]

https://us.forums.blizzard.com/en/hearthstone/t/lost-mana-crystal-with-kaelthas-and-innervatenourish/32078

Hey, I just lost a mana crystal in my supposed big swing kael’thas turn. I started the turn at 9 mana and played Kael’thas -> Rising Winds -> Innervate, so 9-7-2+1=1 mana. Everything working so far.
But then I played Nourish (for 0) and my mana went from 1 to 2? I guess my Innervate mana crystal got lost or something?

Here is the replay link: https://hsreplay.net/replay/nLKA9s72PPAhLttUwkD7yN
It happened right at the end of the replay as I conceded immediately after, thinking I had made a stupid mistake and already being tilted.

I actually repeated almost the exact same turn against the innkeeper, but this time I played Kael’thas -> Innervate -> Rising Winds (this time the non-twinspell version, not like the first time) -> Nourish and I correctly had 3 mana.

Tested to ensure it's not just the Choose Both variant:

This probably shouldn't happen. When at 10 mana, Innervate seamlessly transitions to functioning as "refill 1 mana crystal." The existence of temporary mana crystals likely isn't something the player is intended to plan around.