Hi everyone, I'm new to the forum and need a little help with one of my phalenopsis orchids. I noticed these weird circular spots on an older leaf:
They are a little pressed in but I never saw any insects or pests and they seem a little too perfectly ring shaped anyway, I don't think it's pest related. I cut the most damaged leaf off and I'm monitoring the other one that also has the beginnings of the issue.
Can anyone help identify this? The orchid is otherwise perfectly ok, has healthy roots and is in bloom.