Some insects lay eggs, some insects have live births. Dubia roaches have live births. Inside the adult female, An ootheca or egg casing sits until the babies are ready. Some species of insects such as praying mantis will drop their ootheca and protect it until the young are ready to emerge. Inside the ootheca a protein-like substance begins to harden creating the exoskeleton.
Female dubia roaches when stressed will abandon their ootheca when there are high times of stress or an external force such as a human touches it or breaks it off. Noticing several of these on the bottom of your bins may mean something is wrong. Often this is due to a poor ratio of females to males.
Oothecae (plural version) are often dark red in color. If they are fresh, they may be white/clear.
Females will often push out the ootheca to regulate the temperature, and/or get a feel for if there is enough space for the babies to grow. DO NOT try to touch them, they will likely abandon that set of babies and it will take another month or so for them to be ready to breed again. Seeing females push them out in a bin is a great sign that you will have baby dubia shortly.