How common is a spontaneous alba type?
 

I bought a dendrobium secundum a bit over a year and and its looking like it will be flowing for the first time this year! Intriguingly, the buds look like they will be white, not pink as I expected. Is this a common occurrence or a once in a blue moon situation? Is it more likely the vendor mixed up tags a while ago or that this is a spontaneous expression of the alba type?

If I’m not mistaken, (a common occurrence) albinistic genes tend to be recessive.

It could be a mis-ID, or, if it’s a pale pink that has been grown warm, the anthocyanin might have been suppressed.

Genes dont express differently year to year, so your plant is either double recessive and it would be alba (every time), or it has dominant alleles and it will be normal coloration (tipo).

I think either it is a cultural thing like Ray said or you accidentally got an alba. Also flowers darken as they age so perhaps the buds just havent flushed pink yet?

Congratulations on the flowers either way!

In some orchids, flower color comes from a layer only a single cell deep. Thus, outside of the buds has nothing to do with the eventual color of the open flower.

I do not have this Dendrobium species, so I don't know whether that is the case here.