Table filter not working

i have a table populated by data coming from an API (openstreetmap).
I added a filter, but if i try to filter like "city contains" it is not really working, because it is showing also cities that i'm not requesting, like this

also if i write "Leipzig" in the filter im getting only a few results instead of many more.
Another thing: the sort by i think is not working, if i click on sort by city here is what i get

Is there a fix for this or am i doing something wrong?

ok, i added an id to the column "city" and now it is working fine