A common supposition is that stories about Jesus were circulating in the period between his crucifixion and the writing of the gospels. As a result of many oral transmissions the storie s changed and some were made up. Who then was telling these stories?

Was it Paul’s followers in Corinth, Philippi, Colossae, Thessalonica and other Jewish diaspora communities which Paul visited?
Why does Paul never mention these stories? Differences should have evolved between these places but did no one ask which version was correct?
There may have been some information brought by traders but it seems unlikely that there were significant changes from this route.

Was it people in Jerusalem spreading rumours?
The disciples, led by James, were still a cohesive group during Paul’s last visit in about 58CE.
Paul does not mention any variation in their story so it seems unlikely that any significant changes occurred there.

Was it people in Galilee who knew Jesus before his crucifixion?
They may well have altered stories and invented others, but what then is their connection to the gospels?
Literacy was then so rare that anyone capable of recording these stories must have been wealthy and therefore noteworthy,
but there is no evidence that the disciples or Paul were aware of any such person. If there were significant changes to the stories,
what were they and how did Paul and his followers react? If the information was available in the 50’s CE, why were the gospels not written sooner?
On the other hand, it seems unlikely that records could have been collected in the 60’s CE with war starting.

The gospel writers may have received some information from these routes but another possibility is that some literate supporters in Jerusalem,
who did not trust the disciples, fled into exile at start of war in 66CE, taking their documents with them.
This would explain why neither Paul nor the disciples were aware of this material and why the gospels were written after this time.
In this case, the process of oral transmission was largely irrelevant.