I have always found it useless to search for an artist AND a title. I have been using LW only about 9 months.

I only find other songs come up as you describe if the title says eg Edith Piaff Cover.

I find that the search function is by no means perfect, even after resigning myself to only filing in one field.
For instance a search for a two name artist will bring up many with the same first name but different second names.etc and search for a song title will often bring up artists or albums containing that name. I would welcome a method where you could search an exact phrase with quotation marks as in Google ... perhaps this is a Java thing ... I read recently that it has problems also with Chinese and Japanese characters.

So what help can be given I don't know. I think we need to work around the problems as best we can, and hope the Developers can find ways to make the search funcion more accurate.