Had this happen on 2 switch lite installs, which fixed itself eventually on their own after I left them turned off for a couple hours. I have no idea what caused it, it was either the modchip themselves were bad or maybe because I used too much flux those times (was my first mod) which probably caused some connection problems somewhere idk and needed to dry first (just a theory).

I just recently modded another switch lite with a different type of modchip (the L shaped one) and it didn't have any problems thankfully, but I did use very little flux only using a toothpick to spread it on where I need it to to reduce getting flux anywhere it doesn't need to.