Student or Learner
"It's picked up that they were always late."
What does "it is picked up that..." mean?
Not a teacher
"pick up" stands also for "selecting" and "choosing" a bit of a wider context would help...
so it's slang or an informal phrase?
It may, by some quarters be classified as slang in:
"pick up a girl at a disco"
An opinion I don't share. As for other uses is perfectly current.
I don't either. I would say "meet". But strange as it may sound it is widely used, although, as I've said, censored by some quarters. Just google it.
learn, hear, get word, get wind, find out, get a line, discover, see,