where online wallet is recomended not exchanger, i see litecoin dot org not remonded link wallet online
do not use online wallets and certainly do not use an exchange site for storing any coins not only litecoin because of the risks these methods have.
the wallet is safe and as it was mentioned it is a false report. but you should always check the signature of the wallet file you download to make sure it is not a compromised copy.
also if you have trouble with core you can use Electrum version of the wallet, there is actually an Electrum-ltc wallet available.
Can we make restore from litecoin core to electrum-ltc ?