Backport: Trunk 8369; From Eli2: Mantis 0002538: Fade-in time limitation. Testing in Multiplayer as well, no drastic incompatibility found. (If the host is patched but the client is not, then the timing returns are a little funny, but it doesn't cause for any crashes)
mod - /branches/fs2_open_3_6_14/code/parse/sexp.cpp
