Always like this, trigger QoS as more people browsing at 10 AM morning, sometimes kill China traffic at 12 PM, getting higher and higher QoS over time, then boom at night 7 PM where everyone at home, as they start not using data(during office time) but UniFi/WiFi.
Get reset after a lot of people going rest during 1 AM, now moving earlier as the quota of this QoS is getting lower.
or I should said, easy to trigger as more people getting 100M high speed, compare with 30M.
Before that just applied to Google local ISP(yes, 480KBps, until Google having some deals with TM) + China traffic, then after famous of CloudFlare, moving to whole SG traffic as well.
This rule applied since Streamyx era, then went away for UniFi(only UniFi customer get benefit) showing up, after the famous of free speed upgrade, the effect of QoS came back to UniFi, as Streamyx user start moving to UniFi.
The slowness of IPv6(mostly for upload) for Google also observed during that time(MEGA drive get the most hit, last for years), which is why got the famous "disable IPv6 to speed up the internet" showing up in Lowyat forum.
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If you wanna me guess why it trigger heavy yesterday?
There is 1 thing I know might trigger, 1 famous activity happen during night yesterday, bilibili livestream about the HSR's CNY Festival, the video server is at Amazon SG, only it use Maxis MY CDN if you doing something, which already having high latency by going local, but at least stable than Amazon...
As it is Sunday, the traffic should be local Chinese + Student + Oversea Chinese(SG? also those oversea Chinese getting the traffic wrongly and going to Amazon SG via MY) watching live stream, taking it down heavy.
https://www.bilibili.com/festival/honkaistarrail2024springBut it might also be DDoS traffic la, not like MY don't have a lot of computer infected as BOT, going to printer shop, then going back, see your Pendrive got worm infected or not...

ha ha ha i disable IPv6 also.