The flagset changes probably broke this behavior by not respecting the "inconsistent" value set by the OnInit function when ships have inconsistent values for a specific flag. This should fix that and restore the 3.7.4 behavior.
This introduces a new mechanism for handling bit flags. Instead of using an int (or two, or three) to write bits into, this uses the std::bitset in a wrapper class that accepts an enum class as input. This means that certain classes of errors we've had a few of in the engine, where a coder used the wrong set of flags or checked them against the wrong variable (SF_STEALTH vs SIF_STEALTH, for example) can now be detected at a compiler level rather than not at all.
mjn-mixael