It’s certainly possible someone did a BOM substitution and didn’t due diligence on it, but I doubt it. PCB assembly houses tend to notice components that are suddenly too big for their pads because they’ll have fallout in AOI or later testing.
The underfill was likely added before full production as the result of reliability tests that showed some mechanical susceptibility of that IC.
The underfill was likely added before full production as the result of reliability tests that showed some mechanical susceptibility of that IC.