Following the style of Drake Hawkins' Youtube videos, I started up a game of Factorio with the Rampant mod. I play with the wave difficulty scaling on 3x to make the game extra hard. I hadn't noticed problems before, but in this run, I was 2hrs30m into the game, there was no evidence of any base expansion or more than minimal raids by biters. My settings are otherwise fairly standard, my mods inoffensive, and my pollution level was at 21%.

Drake is also experiencing a complete lack of heavy attacks on his current series. He's on experimental, I'm not. I'm on Factorio 0.17.79. Therefore I suspect this is a bug with the mod.

Savefile: https://gofile.io/?c=oYFoVG
Modlist: https://imgur.com/a/T1EUoFO

I hadn't cleared out any bases myself by this point. Touring round the enemy bases shows no activity beyond what the map would have started with. (By the way, base frequency is at 133% and base size is at 75%.)

I don't see anything in particular that seems to be broken.

The reduced nest count and large distances between nests contribute to the slower combat start.

I see new nests being formed and attacks being generated.

Thanks for checking. I expect I misunderstood the effects of settings like base size.