Mac mini M4 warm during sleep, cool when awake

Does anyone else see this?

My new M4 Mac mini is cool to the touch when in use, yet when it's asleep it's warm to the touch most of the time. I assume this is background tasks, but it does seem odd the fan is not controlling the temperature during sleep, I wonder if the fan is actually off during sleep - but it's silent in typical use, so I cannot tell.

As soon as I wake the machine, the temperature falls to be cool to touch in a few minutes, which supports the fan is likely off during sleep. I am of course worried about the long term unnecessary stress on components by running them hot. Normally I turn my computers off, the only reason this is left on is due to the power button placement, but it's not a major hassle to lift to use, if that is the fix.

I suspect it's iCloud that's running in the background, last night Activity Monitor has logged 465GB data written and 281GB read, I rebooted not long before sleeping - so much of this was durning sleep. This sounds like a lot of data to read/write, even if awake. But it could be initial syncing and indexing, but still a lot! If this was all the time, I can't see the SSD lasting long.

Does anyone else see this? It's by chance I noticed the heat, because typically you don't touch your computer do you?

I do have a support case with Apple, hardware test passed, plus I've tried the following: -

1. Sleep from new blank standard user - does not get warm.
2. Sleep from login screen - does not get warm.
3. Sleep from duplicate main admin account logged into iCloud - gets warm during sleep
4. Sleep with "wake for network access" disabled - did not get warm in 4 hours (short test)

All this indicates it's a software "issue", if it's an issue, the GB of data written could likely be more of an issue, even if the temp isn't.

Anyone got any ideas?