Tongue & grove manufactured hardwood glued to concrete has individual partial boards that have lost contact with glue. How do I repair since removal is not an option? Thx

You glue it back down. But since it never should have been glued down to begin with, you will be doing this forever, especially if your concrete was poured before the days of vapor barrier under it.

Over concrete, wood-based flooring of any kind should have a heavy plastic-with-foam sheeting under it, and the flooring should be floating, either click in place or glued in the groove only.