It's not wrong as explained on this page under §5. But to me it tends to sound a bit odd if somebody does this consistently. I'm Dutch and in Dutch the usage of the word that in cases like these is very common. So this is one of the telltale signs somebody is native Dutchman speaking english.

Disclaimer: I sometimes find, I tend to think anything that sounds Dutch isn't proper English. So I might be slightly biased on this one:).

It's not technically wrong. I think function of that you are referring to is that of a noun clause as described on this page under §5. However, to me it tends to sound a bit odd if somebody does this consistently. 

I'm Dutch and in Dutch the usage of the word that in cases like these is very common. So this is one of the telltale signs of a fellow native Dutchman speaking english:).

Disclaimer: I sometimes find, I tend to think anything that sounds Dutch isn't proper English. So I might be slightly biased on this one:).