Yellow growing in centre of leaf!

[jssj]

Hi All!

Last year I separated my first Keiki from another orchid I have, and it was growing great until recently a large yellow spot appeared in the centre of a main leaf.

At first I thought it was sun burn, so I moved it to a more shady place - but it just kept getting worse!

Now it looks more like something fungal or bacterial, the roots have no rot though!

I've read elsewhere that if it is an infection you should cut off the infected part, but with the orchid being so small and the leaf being it's biggest I'm wondering if I might do it more harm than good by cutting it off?

I've attached some photos for reference of the leaf and roots! What do you guys think? Should I cut it off?

Thanks in advance!
Jenni