I can almost promise you this is a bug. Why? Because the return for Rich Thermoplast Flux missions also got cut in half. It went from 32 to 16 for a non-crit. Why am I confident this is a bug? Because a Bountiful Thermoplast Flux mission still returns 24. So either it's a bug, or they blew the nerf, having a Bountiful return more makes no sense. And no, this isn't a mislabeled mission like the old Rich Grade 6 missions were, as the Rich missions are more expensive than the Bountiful.
I think that's a crit but the numbers seem correct for a crit? Are only non-crits affected?
Bingo, I just had a Rich Thermoplast Flux mission crit, and it returned 40, which was the pre-patch number for a crit for that mission. So it looks like the results are getting cut in half for all non-crit Rich missions that I can remember the pre-patch numbers for, crits aren't being affected, and non-Rich missions aren't being affected.