My understanding is: it is a click/floating floor - Bostic Underlayment (no glue)
Additionally, My floor is Bamboo Strand (not considered an "engineered" wood and therefore does not have the formaldehyde problems that are in the news right now??) I am learning way too much about the hardwood flooring industry (the hard way), thanks for helping to educate me.
Never heard of Bostik underlayment as in roll form. But yes, anthing thats not wholly milled out of a solid piece of wood or bamboo is considered engineered. Strand is shredded and then glued back up, you can call it solid strand if it makes you feel better. And yes there's formaldehyde in almost every flooring. You can have it checked out in a lab.
That said many underlayments suggest a moisture test prior to installation as had been mentioned. Installer should document or else its all just hear say,