New engineered hardwood nailed over linoleium - one loose board
I recently had very competent installers put engineered, square-edge hardwood over a vinyl floor. It is very securely nailed in most places, but the end of one board, right in front of the kitchen sink, has about 1/16" - 1/8" of give and it makes a popping noise when I step on it. The boards around it don't seem to have this problem. If it were in an untraveled area, it would be ok but I will step on it 20 times a day. This house is 50 years old and the floor squeaked in a few places before, so I'll probably get over the noise. However:
1. Will this loose end cause real problems later?
2. If so, is there any way to tighten this board without asking him to tear up a lot of the floor?
They are coming back to finish another area tomorrow, so I have time to ask them if they can fix it. I just want to be knowledgeable about it before I ask.