> Misaligning only some pads while others are perfectly aligned isn’t possible
It's possible when your pcb-making process is on the odge of what designer wanted. Some pads on some boards may be not perfectly aligned in such cases. Or the board was heated not enough or in too short time and not all balls melted properly. Or it cracked under stresses because designer put too much vias in one place near the chip.
> It’s an all-or-nothing situation—either everything aligns, or nothing does.
In theory, practice and theory agrees. In practice, it sometimes does not.
I believe you forgot to quote "unless something’s seriously wrong". Your counter examples seem to describe exactly that: something going seriously wrong.
It's possible when your pcb-making process is on the odge of what designer wanted. Some pads on some boards may be not perfectly aligned in such cases. Or the board was heated not enough or in too short time and not all balls melted properly. Or it cracked under stresses because designer put too much vias in one place near the chip.
> It’s an all-or-nothing situation—either everything aligns, or nothing does.
In theory, practice and theory agrees. In practice, it sometimes does not.