I have a Canon 5D Mark IV with a Sea and Sea MDX 5D housing, Sea and Sea TTL optic converter & 2 YS-D2 strobes.
I've been having intermittent problems with exposures in TTL mode for all ranges-macro as well as wide angle. I have all the modes set correctly Blue, blue, blue, but sometimes the left strobe not synching fully or at least exposures are under, or sometimes it looks like they didn't fire at all.... Through process of elimination, I've replaced the converter, swapped cables, even replaced the strobe. If I switch to manual Green, green, green, everything looks much better exposure wise and consistency. I don't mind this but I'm surprised that the TTL isn't working better. I don't think it would be my camera, but anyone with similar gear that could give insight would be greatly appreciated.