Winter rest for Dendrobium nobile

[MrHungx]

I bought a Den. Fancy Angel ‘Lycée' from Trader Joe's a few months ago. It finished flowering last month. It has 1 mature pseudobulb, 2 smaller leafless back bulbs, and one new growth that has yet to mature. It also had a mature flowering keiki that I ended up separating and giving to my aunt. The leaves on the larger mature pseudobulb are starting to yellow and fall off. Is this Dendrobium entering its winter rest? Or is there some other cause for concern? I guess I'm just not used to orchids that need a winter rest blooming off season.