Yep, it reports every unit change (in Matter, like in Zigbee, it’s not a percentage but 0 to 254), so at least it’s a finite amount, no more than 254 reports in total spaced during the transition time, so if it’s a wind-down routine of 30 minutes it’s not really a problem. With colors (can’t do that with stock drivers) it’s worse, it’s an almost infinite flow of hue/sat values and the hub just can’t keep up, becomes sluggish and takes quite long to catch up.
Wrote a whole post about that time ago:
And also reported it to WiZ, they are aware and I’ve reminded them a few times these months.
My Aeotec hub is not particularly powerful, so it struggles even more with some transitions. In Home Assistant they decided to stop recording in the database attributes like brightness because any transition, even if it’s not especially spammy, would be a lot of useless data.