Have been thinking about this. Not sure whether there is a relationship between richer
soil(high in compost) that will kill newly rooted cuttings when moved to 1 gal pot. It had
happened more than once when a whole batch of newly planted cuttings in 1 gal pot wilted
and "sayonara". Drainage was good plus humidity was high. I think there is a relationship that
higher compost may have resulted in the tender roots being "cooked" when weather warms up.
My view is not based on any scientific research -- just a thought.

Curious what was your compost ratio when they died? I repotted some yesterday into 1 gal pots with about 30% compost.
I made compost myself from some wood shavings + grass clippings + leaves + kitchen scraps. It is about 1 year old.

my new cuttings go into 50/50 seedling soil and perlite. not because i don't want rich soil, but because they were in same soil mix while in the cup. and since i use peat pot method, staying with same soil mix prevent watering issue. but i do start fertilizing and lime within few weeks of going into 1 gal.

maybe compost is generating too much heat or introducing things that new roots can't handle?

Might depend on how well composted the compost is. If it is still composting, the roots are just one more item to compost.

Paully,

In agriculture one tries to shoot for a soil mix with roughly 5 - 10% organic matter. Even in ideal conditions soil which is collected outside human activity will have amounts of 3 - 5%