Tag is moving when text with newline character is inserted

According to the help tags are associated with a given line.

Now I see that tags move a line down if I insert some text which contains a newline...

Let me try to illustrate the observed behavior:

TAG   xxxxxxxxxx1

          xxxxxxxxxx2

becomes

          xxxxxxxxxx1yyyyy

TAG   yyxxxxxxxxxx2

Is this the intended behavior? Somehow I find it counter-intuitive, I would prefer tags being associated with the beginning of a line, not with its end.

This line year is ending, may the next bring us many reasons of being grateful.