Fundamentally, the delay of Defiant in addition to the extremely protracted flight testing of Raider makes the issues seem far less likely due to management and much more technical oriented - totally contrary to the statements made by management of Sikorsky/Boeing/Lockheed. Occams razor.
But would we really expect them to be transparent if they hit design roadblocks? No, rather we get to enjoy the
PR blitz of fancy movies in lieu of actual progress.
For example, The SB1 team has had their fuselage for 4 months now, and they have released precisely one photo of it on delivery day and included zero images of any physical hardware whatsoever in their latest marketing video. We saw S97 touted widely during construction.
Part of downselect for FVL is the ability for a team to manufacture on time and on budget. So to keep everything hidden if there really is no technical issue would be quite puzzling.