Liner blistering & double facer relations

The blistering is due to the poor bonding (not due to the whole web poor bonding). Liner is partial bonding well with medium, but there is still unbounded area which makes the liner separate from the medium in irregular bulge. Supposed that the blistering is due to the machine break down and adhesive agent problem, then the phenomenon is linked with double facer and the main reasons lie on the temperature, tension and heat plate temperature.