Can anyone name a single time when the apostles as a group, under prayer and claiming God's direction as a group, ever established a belief or clarification, and then a few years later received "new light", or a different understanding of any kind, thus causing them to redirect individuals or congregations on a different course than they had previously established as from God?
It seems you have carefully worded your question so as to elicit a negative answer... ;)
Afaik the idea of apostles acting "as a group" is only found in the book of Acts and there they are indeed not portrayed as contradicting themselves as a group from one moment to another; disagreement between them is carefully limited to trivial matters (e.g. Paul and Barnabas) or smoothly resolved (e.g. Peter and James).
However, if you consider the whole NT "apostolic" material in some sense (as the early church did) you may get a pretty different picture. Not that of a "governing body" changing its mind as time goes but of individual "apostles" and movements which had actually little in common, and often are found in strong disagreement with each other when they happen to deal with similar topics (e.g. Matthew vs. Romans on the validity of the Law, James vs. Romans on faith and works, the so-called "apostolic decree" and Revelation vs. 1 Corinthians on food sacrificed to idols, and so on). You have also different and mutually exclusive views integrated in the same work (e.g. the Son of Man will come before the preaching of the Gospel to Israel, Samaria excluded, is over, Matthew 10; after the preaching is extended to the diaspora as a testimony to the Gentiles, but immediately after Jerusalem's fall, chapter 24; after the preaching is extended to all the Gentiles, without any chronological indication, 28:18ff -- all of this on Jesus' lips btw). You have also very strong differences between works ascribed to the same person, e.g. the correction of the eschatology of 1 Thessalonians (the day of the Lord will come anytime, without any forewarning sign) in 2 Thessalonians (the day of the Lord cannot come now because the 'man of lawlessness' must come before, and he cannot come now for some mysterious reason). So there are indeed indications of doctrinal revision within most if not all segments of the early Christian nebula. What is actually lacking is the evidence for any constituted group of "apostles" beint acknowledged as a collective overarching authority by all of them -- iow, we do not see the Twelve (as per the storyline of the Gospels and Acts) working practically in such function over the universal church.