Vortigern Aedui states:

This question might be inconsequential pertaining the topic, but the Aedui? I find this to be shocking that the Aedui would revolt against Rome, and in such a large number, considering the alliance between the tribe and Rome that dates beyond Caesar's conquest.

I am wondering what incident(s) may have turned the Aedui from Rome?

The primary information I've found on this revolt was from Tacitus. Other books, including Wells' Barbarians Speak and Scarre's Chronicle of the Roman Emperors, mention only the revolt itself, without the reasons for each tribe's uprising.

Why would the Aedui join in the revolt when they had enjoyed the benefits of Rome's friendship in the past? Possibly due to tax burden

Germanicus, Tiberius' adopted son and Augustus' great-newphew, remained with the Rhine army from 14-16 CE, conducting successive campaigns deeper into Germany.[1] He recovered two of the three legionary standards lost at the battlfe of Teutoburg forest. While this made Germanicus a popular hero in Rome, the provinces had to be heavily taxed to cover the expenses.

In protest, Sacrovir roused Gaul into revolt. At the beginning, Sacrovir arranged secret meetings with people who would be sympathetic. He touted the idea of freedom from Roman oppression, cruelty and arrogance of the governors, hinting about disaffection amongst the soldiers (based upon the murder of Germanicus). At these meetings, Sacrovir and his co-conspirators also said it was "a grand opportunity for the recovery freedom." [2] This movement found considerable support among the Aedui.

A more formidable movement broke out among the Aedui, proportioned to the greater wealth of the state and the distance of the force which should repress it. Sacrovir with some armed cohorts had made himself master of Augustodunum, the capital of the tribe, with the noblest youth of Gaul, there devoting themselves to a liberal education, and with such hostages he proposed to unite in his cause their parents and kinsfolk. He also distributed among the youth arms which he had had secretly manufactured. There were forty thousand, one fifth armed like our legionaries; the rest had spears and knives and other weapons used in the chase. In addition were some slaves who were being trained for gladiators, clad after the national fashion in a complete covering of steel. ... This army was continually increased, not yet by any open combination of the neighbouring states, but by zealous individual enthusiasm, as well as by strife between the Roman generals, each of whom claimed the war for himself. [Tacitus, The Annals, Chapter III]

1. Scarre, C. (1995). Chronicle of the Roman emperors : the reign-by-reign record of the rulers of Imperial Rome. London ; New York, Thames and Hudson.
2. Tacitus. The Annals. Translated by Alfred John Church and William Jackson Brodribb. Web site edition, MIT Internet Classics.
3. Wells, P. S. (1999). The Barbarians Speak : how the conquered peoples shaped Roman Europe. Princeton, N.J., Princeton University Press.