This reads "ΠΑΠΑΔΟΠΟΥΛΟΥ / PAPADOPOULOU". I suppose this is just a ligature of omicron and upsilon on the font level:
Despite the ligature's origin in Greek, there is no separate provision
for its encoding in the Greek script, because it was deemed to be a mere
ligature on the font level but not a separate underlying character. A
proposal for encoding it as "Greek letter ou" was made in 1998, but was rejected. — https://en.wikipedia.org/wiki/Ou_(ligature)
As much as I could deduce, the use case above is just a branding decision? Did you ever happen to provide this ligature in your fonts, or any other ligatures for Greek? If so, did you put it in liga, dlig, or elsewhere?
I would appreciate native speakers' opinions on how this Ο_Υ ligature
affects the logotype's impression. I suppose the Greek are rather well
acquainted with it? But this is a different situation than with Latin
f-ligatures, which are (or at least supposed to be) transparent to the
average reader. Edit: I'm not sure if History of Typography is the right category choice for this topic, maybe Technique & Theory suits better. What I initially had in mind when I started writing was a bit different.