Cymbidium with black spots on leaf tips

[Xylocarp]

Hi! So I'm a complete plant beginner, yet somehow got suckered into buying a beautiful cymbidium about a month ago. Over the past couple of weeks I've been keeping an eye on some black spots on leaves —*but I haven't been too worried about them, as some extensive googling tells me its quite normal for a cym to be a little bit spotty.

I took a photo of a particular leaf tip about a week ago — image 01 attached.

Today, this wing tip has yellowed and developed a large brown spot — image 02 attached.

I've now removed this leaf tip just in case. Does this look like any kind of bacterial/fungal infection? Other than these black spots and now this yellowing tip, my cym seems to be quite happy in his spot next to a frosted window, with flowers still perfect after a month and the leaves a nice apple-y green.

In terms of watering, I've had him a month and only watered twice — the last was two weeks ago, but I'm waiting a few more days to water as the top of his soil is only just dry.

I appreciate any help you can offer!