Hi all - I have engineered white oak wood floors glued down over concrete. They are about 3 years old now and have been performing pretty well. In one high traffic area, one of the edges of a board seems to be a little bit lifted up / not flush, and recently when walking over it I've noticed it's making a crunching / crackling sound in the area where it's lifting. Any ideas what's going on here? Is this delamination? What's the fix here short of replacing the board? Glue? I've had good luck with Dritac in the past, but isn't that more for issues with subfloor adhesion? Photo: https://imgur.com/a/Hlb1YdV

Thanks!

If the veneer on top is lifting you would do better to use epoxy for a repair. Could this be from water damage?
A general purpose epoxy will hold it down if you can get the epoxy under the loose section. You may need to drill a small hole through the veneer.

Thanks Pete for the response. There has not been any water damage to my knowledge - to be honest I think it has looked like this since installation several years ago, but never made a noise until recently so it never really bothered me. Now that it's making a noise I'd like to silence it. Would Dritac be the appropriate choice here? I assume I'd be drilling less deep a hole since the problem is closer to the top. Or alternatively, what about a finishing nail? Thank you!

A finishing nail is the easiest and then set and fill the nail hole with pre-finished colored wood patch.