The tables in text that flows in more columns will naturally break between columns. On the following screenshot the second table breaks in the 7th row between the first and the second column.

To avoid the table breaking, use the >kn< and >ktt< and >default< tags before any table header and definition. On the following screenshot we added >kn 1<>ktt4<>default< before all text that precedes the second table (e.g. TABLE HEADER 2): the table automatically jumps to the second column and won't break anymore. However, the empty space remains on the bottom of the column - that is unavoidable.

You have to plan the table columns carefully, to avoid both the tables breaking and the empty space.