What website said this was OK? I
would never do such a thing (even with a mastic).
Just because a contractor does it, does not mean
it's OK. My guess is your neighbor will be having his
tiles come loose also.

What benefit did you expect to realize? As you found out
the linolium is not a good surface to bond to and being the
anal type, I dont like another bond between my tile and
structually sound material