Many cannabis cultivators complain the LENS of 660nm fall off easily.
It may be that the nozzle touched LENS during SMT. It may also be knocked off during assembly on the production line. There is also a possibility that the grower touched LENS himself.
We used a special glue spayed on the PCB to enhance the thrust from 20.53N to 33.4N. The surface is very smooth and not sticky.