Ah, that’s your problem. Using immersion blenders & a kitchen aid is not the right type of mixer for systems that are made up of a high level of surfactants. You need slower mixer which does not draw in a large amount of air.
What is happening is you are whipping so much air into your system that the bubbles are tiny and compact such that you can’t easily see them. If you looked at a sample under a microscope you would likely see air bubbles throughout the sample.
Over time, in the jar, air bubbles combine (coalesce) which forms larger bubbles to the point where you’re able to see them.
Solution - don’t use an immersion blender or kitchen aid to mix your ingredients. Use a center stir mixer, keep the mixing paddle below the surface of the liquid and keep the mixing speed slow.