Kevin,
So far not seeing much rot or sun damage in these groups, I pretty much just have the three crosses in my first generation of 'Lilac Time' kids, that's 'Hordubal', 'Silverine' and 'Grey Lady'. I watched a plant or two from the 'Grey Lady' crosses loose some leaves and one flat rounded rosette from 'Silverine' struggled a bit in late winter (which is frustrating because it has the most distinctive form of any in that group). All of the 'Hordubal' kids are impervious, a couple have turned out to be slow growing runts, but none have shown any signs of rot.
The next two years crosses were mostly to blues and velvets. I took it to 'Silver Song' this year, as well as a couple other light colored ones though.
Proving your point, I self crossed 'Lilac Time' last year; the seeds germinated then died much like my 'Lemon Sky' seeds did. Thanks for the tip, next year I suspect lots of seedlings will bloom. I can focus my powdery 'Lilac Time' selections to cross with the best of the 'Silverine' bee seed instead of with each other.
-Sol