The droplets are caused by polyurethane flowing into the gaps between floorboards while the floor is moving.
Glue down hardwood floor problems.
Buckling occurs when the wood flooring actually pulls up from the subfloor lifting several inches in one or more places.
The problem generally occurs when a floor is being finished during the change between dry and humid seasons.
Floor buckling is the most extreme reaction to moisture in a hardwood floor.
When small polyurethane droplets form along the edges of each floorboard moisture is always to blame.
The glue down method of engineered wood flooring installation is typically the most common and creates a highly stable floor.
Glue down hardwood floor installation reduces but does not eliminate wood movement the adhesives used to glue wood down to a subfloor make for an extremely strong bond.
Boards adhere well to the rough surface of the concrete subfloor and therefore lead to less gaps or planks lifting and buckling.
The elasticity in hardwood flooring glue ensures that the hardwood will have an ample amount of space to expand and contract without causing the glue to crack or separate.
Fortunately this is not a common occurrence.
Floor buckling happens most often after a floor has been flooded for an extended period of time.