As of around the End of January, ASUSWRT-Merlin firmware switched to the new 386 codebase.
Now the reason why I a posting is I was on version 384.19 and after the upgrade I noticed my CPUs where running very high and access to router UI was slow,
Luckily I had already read the Changelog and part of the change from 384 to 386 codebase requires the new firmware to undergo some behind the scenes database maintenance, so I shall give it an hour and see what occurs
NOTE: Some users upgrading might have to go through some database maintenance on first boot, which means the router might be slower or have a non-responsive webui for a while.
This can take anywhere from 5 minutes up to an hour, depending on your model, just give it time to complete the process.
In a completely sane world, madness is the only freedom (J.G.Ballard).