Except no aphids to be seen and plant and roots were thoroughly cleaned with alcohol and hydrogen peroxide before being repotted…

Any other thoughts?

Hi there, I recently noticed something similar on my own Asteria... See below. Also sticky, gets washed off relatively easily with water and cotton, but comes back after a couple of days. Did someone figure out what this could be? Is it common in Astoria? Anything to be worried of? Thank you! Asteri...