Games that use real time are not working

I left my ds dead for around 4 months. I got on it a few days ago and my animal crossing time was set to 2012. I changed the time ingame and moved on.

I checked my DS time after that and it was still correct (as in it was set to right date, unlike the game). I thought my game was just glitching out.

Fast forword to today, i get oin ACNL today and it says 2026. Instead of dealing with it I just got off and put in pokemon ultra moon, assuming my ACNL was busted.

Only, upon going to the festival plaza, i find that my game registers me as time skipping, since all the places register as everything is sold out/unavailable, like it does when you time skip to punish you.

Only, I didn't time skip.

I tried other games to get the same results.

Pokemon even says the correct time and date when I go to save…

So I had come to the conclusion that it has to be my 3ds.

I've never had an issue with my 3ds, and these started with a system update that I had to do after my ds was left dead for 4 months.

I've double checked my time before posting this and it is still correct.

Is anyone able to tell me how to fix this, or what the actual issue is?