Bulbo. Elizabeth Ann 'Buckleberry'

[WeirdGuySeattle]

Got a new plant - 2 weeks ago and immediately potted in a cedar basket. Growing in a GH - most nights > 57, though colder nights have seen it dip to 55. Day temps get to ~72. Summer will obviously be warmer.

This morning, I noticed the oldest leaf in the 3 bulb division I bought is rapidly discoloring, yellowing from the middle of the leaf outwards.

Am I growing it too cold? Should I bring inside the house (min temps = 66, but going to be house humidity - 40% or something).
Or is this just a plant adjusting to the shock in changing growing conditions and should calm down as it gets used to my space?
I don't want to lose any more leaves. I can try to take pictures and update tomorrow / tonight.