Wood floor sadness...
 

Im trying to install Home Legend floating click lock wood floor in my kitchen(about 75sqft). When I was working on the plywood subfloor I noticed that two of the joists had sunk a bit causing a depression(about 5/16'' at its deepest point). I used roofing shingles per many opinions on the internet and used a string to flatten out the depression as best as I could. I put down the underlayment and laid the floor.

Now I have laid all the floor and here is my problem. When I walk on the floor I feel like it is giving a little bit as I step on it. Its not a lot, maybe 1/8'' give in the "squishiest" spots. This happens in random spots and is not specific to where the depression was. I only used strait planks and discarded the warped ones.

So my question is... Is this normal for the floor to give a little and its all in my head? Or is the most likely cause that the subfloor still isnt level? Or is there some other possible cause Ive never heard of?

Perhaps you still have movement in a floor joist when you walk on it, if so you might be able to stiffin it from below.

All of this should have been addressed before the floor went in. Sags can be caused from the wrong subflooring such a partical board, to thin or moisture damage due to no vaper barrier on the ground if it's a crawl space.
Bounce in the floor is from to long a span and or undersized floor joist. More footing and piers were needed with a doubled up beam running down the center of the span.