Maybe the issue was legit, malware ad or something.
It could very well be legit. In these conspiratard days, even Google should provide a reason when they do such things, to ward off suspicion.
Well... They did say "Malware". They do a ton of those, there is a staggering amount of that. About 10% of the web (by volume, not popularity) contains malware.
If it was legit, then actions were taken by machines.
The quick resolution makes me think there was no foul play involved.