Yes, it could very well be, especially if the problems happened right after a fall in temps. Normally, going below freezing is ok for the leaves but only up to a point.

I would water it the night before a fall in temps and make sure it has 3-4" of mulch. The damaged leaves cannot be fixed. You can either leave them there or cthem off. Buds will also brown out if the temps go down too low or if the temps begin a song and dance that takes real high and then back real low.

Wow, I'm smacking myself in the head right now. Mulch! Why didn't I think to protect with mulch?

I have 2 of these new camelias and this one has more brown, dead buds that fall off easily.

I think I'll trim back the dead leaves in a week or two and hope it recovers.

Most of the camelias look ok.

Where are you and what is your zone, mimipadv? Another thing to keep in mind is when do they bloom, how is your winter climate (ie, how cold does it get).

Early blooming and late blooming camellias are very useful in cold climates. Early/late blooming helps prevent browning of flower buds because they shrubs bloom at times when temps are not at their lowest. If you get this problem regularly, consider the early and late blooming camellias.

Where I am located, for example, winter is somewhat mild so flower buds do not brown out. Usually. Instead, the plant goes "dormant". Meaning it stops blooming and restarts in a month or so, depending on temps. I had one that started in late December, bloomed part of January and stopped. Then it restarted in March.