Nothing in that episode said anything about the intro. Perhaps you should watch the intro again?

And read about the intro here:
https://www.artofthetitle.com/title/star-trek-discovery/
Right, so the person in charge of the sequence misspoke, like that's never happened before. Remember the enormous debate from the
Picard finale, where Ante Dekovic (one of the VFX supervisors who worked on the show) implied that there were four distinct starship designs in Riker's fleet, when there was really only one with two nacelle variants? When what everyone thinks he
should have said was that four designs were
submitted, which seems to be the real truth of it. Just a simple mistake where he misremembered what his team ultimately did, he's only human, no big deal.
Same thing here. The showrunners most likely told Criado to put blue crystals in the intro because of the upcoming use and significance of the time crystals in the season and she
assumed that they were dilithium. They weren't revealed as time crystals until the latter third of the season, long after the intro was complete. Ever since Season 1, damn near everything had significance in that intro, even the little numbers floating around for stellar coordinates. Dilithium is the big one
this season - The color change is
not coincidental. I will concede that it's possible that, since the blue crystals were there since the S1 intro, they may have originally intended for them to be dilithium. They then used blue crystals in S2 to represent the time crystals (no need to change that part of the intro, because the color matched), and by the time S3 rolled around and dilithium crystals were needed to play a significant role, someone said, "Shit! We need to change the color of those things to differentiate them from what we used last season!" Hence, the change to red.
Look, (I can't believe I'm going down into the weeds with this) in literally every single scene that dilithium crystals have been shown, they were red, reddish-pink, clearish-pink, reddish-orange or yellowish-orange, always in the warm color range. There has
never been a time that they were shown blue, in the cool color range.
TOS - The Alternative Factor (Season 1):
TOS - Elaan of Troyius (Season 3):

I'm only going to show those two TOS pics, as they used the same (red) props to represent functional dilithium throughout the entire series run. Moving on...
Star Trek IV: The Voyage Home:
Granted, these are a little more yellowish-orange, but they're Klingon crystals and might be processed differently. They're also lit from inside, so they could just be clear. in any case, still,
#NotBlue.
TNG - Skin of Evil (Season 1):
I did find this one online - apparently a crystal prop from
Star Trek Enterprise that's clear-ish, with some pink hues to it. The smaller picture of the entire lot shows crystals ranging from clear to rose-pink. No idea which episode these came from:
Close-up of lot:
Star Trek Discovery has gone out of their way this season to show dilithium as red. I haven't found good recent screencaps that show the dilithium, but from what I recall, it is red.
The
only blue crystals we've ever seen are the time crystals from Boreth, starting with S2's "
Through the Valley of Shadows":
Ugh... I'm tired now.