CMC should not really be used as a single source of truth for these matters ... nor for any other to be honest.
Coingecko was working perfectly at the time. I was surprised that Trustwallet suffered the same fake price just as Coinmarketcap, people saw their price balance on the wallet skyrocketed with the fake price.
And it was not really much of a problem for as long as there was no vital data that was leaked, or no trading or investing decision was made by people while that glitch happened.
I do not think it affected trading, it only happened on Coinmarketcap and wallet like Trustwallet, anyone that thought he can make use of the period as an advantage to trade and get bigger amount was deceiving himself because the normal onchain value would be the one that would later result to. On Binance, the price were normal. So no trading manipulation.
About hack, it is as usual, Coinmarketcap database has been hacked before and many users details were stolen by the hackers involved. The best is for people not to submit their personal information like emails on the site, else, hack should be expected.