The reasons for the delamination of multi-layer board bulges

What are the reasons for the delamination of multi-layer board bulges? Regarding this, relevant sources have stated that:

The main reasons for this phenomenon are focused on the selection of veneers, the selection of bonding solvents, and the control of hot pressing time. In the processing technology of veneers, the amount of moisture content in the veneers and insufficient drying can lead to foaming. If the bonding solvent is applied too much, or exceeds the optimal bonding temperature and time of the bonding solvent, it can cause the phenomenon of plywood delamination.

The control of hot pressing time is directly related to the drying degree of the veneer, and production personnel need to ensure the reasonable use of the hot press machine and the veneer product to determine the optimal hot pressing time.