My sd card is 100% real.
However I never installed the updates and the switch gave me an sd card error. The games worked for 3 days.
Did this happen because I didn't install updates ?
in short I believe yes.
I had same issues, reinstalling sig patches and then the nsp fixes it for another couple of days, but I found that doing that and updating the games they work 100%.
My theory is the game was dumped after being updated and the game files know the update files are required.
My advice: always update to latest patch ASAP.
edit: to clarify if the game was 1.0.0 when dumped, you would have no issue. If the game was updated to 1.0.1 and the base 1.0.0 and update 1.0.1 is dumped the base 1.0.0 is somehow tied to require the 1.0.1 update like it or not.