In my experience, out-gassing is a term generally used to describe the process of volatile compounds (those that easily evaporate) migrating out of a floor over time and is therefore more of a health and safety issue than anything to do with defects. A common example of out-gassing in another context is the new car smell we all know and love. While this smell disappears over a few months, the materials in your car are still releasing these volatile compounds for a long time without you noticing it.
Thinking about an epoxy floor in the same way, there are volatile compounds that slowly move through the film and get released into atmosphere. Depending on the product they can be toxic or harmless; there can be a lot or just a little; they may all come out in the first 12 months or trickle out over a decade. There’s a great deal of variation in this sense, but the important thing to remember is it happens gradually and not within the space of 24 hours. If you can picture this then you can understand why I say out-gassing isn’t the cause of bubbles in your floor.