The TLE used in the linked observation was fetched 20 hours before the pass, so it should’ve been sufficiently accurate (unless Celestrak returned an old TLE).
TLEs are fetched automatically from Celestrak at least once a day.
I just checked, at the moment the TLE for 3CAT-1 is only 6 hours old, so the mechanism works:
For 3CAT-1 we use the TLEs of the object with COSPAR designation 2018-096AA / NORAD ID 43743 at the moment. As the satellites from this launch were in the orbit for some time now, were you already able to definitely ID 3CAT-1 being object 43743?