It takes a little while for the slow basal trickle to start getting absorbed. I do what I call an “activation bolus”.
If you change your pod right before a meal, you don’t need to do it. But if you change the pod and will not be bolusing for a while, take a small bit - like 0.25 or 0.50 or something - right when you start the pod. That will help get everything going. This has helped me with the same problem.
Seems like it could be an issue for some people with any pump. Sounds like the same thing @Katers87 mentioned.