Magnet explorer have some issue at least the first version
Try this one balance is more accurate http://explorer2.magnetwork.io/
That's the one I used. Anyway, the wallet have updated and now shows the same balance as shown on explorer. I think it was a glitch as all the latest transactions were visible in wallet even before it updated to current balance. Took it about 2 hours though
I am having the same issue. My balance is significantly less than what the block explorer shows. I have waited more than 4 hours. I do see all the transactions though so hopefully final balance will get updated soon.