Julia, this year I am seeing that in a number of semps. 'Little Princess' and several others are the same as yours. Big mature rosettes, when you go to harvest the rosettes are not not individually rooted like we are used to seeing.
In the last two months I have removed some and planted them, they have all taken off growing their own roots now.
Weird.
In the past I have seen some of the arachnoideum types do this.
