With your insertion point anywhere in the table & you go to
Table>Select>Table does the entire table get selected - first row to the
very last row?
*If not: Do you see a ¶ below any of the rows? You actually have more than
one table & each one will have to be formatted as below or they will have to
be joined as a single table.
*If so: Then go to Table>Table Properties>Rows, clear the Allow to Break
checkbox (make sure it is *cleared*, not simply grayed)...
This should resolve it unless something about the source you copied or the
manner in which you pasted caused the "half-rows" to be treated as separate
rows. It's impossible to tell without knowing more about the source, but if
it wasn't a true table that's quite possible. Should that be the case it's a
tedious process, but you can select 2 cells at a time (one above the other
where the breaks occur) and use Table>Merge Cells for each pair of cells in
each of the affected rows - don't try to do the complete pair of rows at
once...
It may be faster to repaste as Edit>Paste Special - Unformatted Text, remove
the offending ¶s, use Table>Convert>Text to Table to get it back into a
table form & format as required.