I know the blueberry plant is considered "deciduous" but should it lose its final leaves in February in Northern California?

I bought this one only a couple of weeks ago and by all other standards, it's flourishing and loves the acidic soil, etc.

However, for the past 3 mornings, I wake up to one otherwise healthy red leaf having dropped. Keep in mind this tree came with only red leaves -- and all the green you see is actually new growth since I've repotted.

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I've never grown blueberries before so I am not sure what to make of it.

It looks extremely happy otherwise but I wanted to make sure the reddish leaves dropping is not of concern. It is quite cold here the last few days -- like high of low 50s and definitely dipping into the 40s overnight, FYI.

Thank you! I was totally unsure if this was last year's growth or if the leaves on this particular one were meant to be reddish. :-)

This one is Southmoon, and it's planted alongside Misty. I'm still on the lookout for "O'Neal"? Based on what I read, I really want that one but in all honesty, I'd be crazy to bring in one more on this patio given how cramped I am right now, haha.

We have really been fluctuating in temperature here in the SF Bay Area -- from highs of mid 70s to highs of 50 all in the same week. Yesterday was a high of 52 and I really was concerned about some of the plants -- and today, it's like summer out there!

Thank you again for your response!

Shazaam -- that's a relief to hear! When I got it, a few buds were setting and it was interimittently peppers with reddish leaves, so I thought perhaps that's the color of this bush. So when they started dropping, I had to consult the blueberry experts here.
The Southmoon and Misty are also sharing the same wine barrel planter at this time. I'm not entirely certain that this was my most brilliant idea, but I'm really limited on space on that particular balcony, and the other doesn't receive enough sunshine for me to move them all there. I figure this setup is okay for the next year or two, and am relieved to know you have done this already. If I get the O'Neal, which I shouldn't but probably will, that one will have its own pot, mostly because I don't feel like messing w/ this pot, haha.

I think if I had all three on hand on the day I planted, I would have probably tried to squeeze them all into one pot!

I am really, really loving how the Southmoon spurts out new growth along seemingly old branches. It's really a dramatic change, day by day, whereas less so w/ the Misty that has retained all its leaves and was lush and pretty to begin with.

Fingers crossed!