IMHO vacuum stabilizing with Minwax wood hardener is ineffective and dangerous. It contains a high concentration of acetone that will start to boil prior to achieving deep vacuum. This is similar to vacuum stabilizing wet wood - the water in the wood turns to gas and makes it difficult to remove all of the air. Also, water boils at a higher temperature (lower pressure) than acetone, so the MW wood hardener will behave even worse. Also, the acetone that boils off will travel through you vacuum pump and may pose a fire/explosion hazard.
Did you dry the wood completely prior to applying the MW? Like bone-dry --> heat to over 212 degF for several hours (I do 12 hrs). Moisture in the wood can cause casting resin to foam, but in your case it looks like air bubbles rather than foaming. I think that it is recommended to dry wood completely prior to any kind of stabilization as it will allow the wood to soak up more of the stabilizer. Note - cool blanks in a plastic bag prior to stabilizing.
I have had success casting small quantities of unstabilized wood with epoxy without using a pressure pot. Doing only a single blank at a time. I used the method described in the video below, using Art-N-Glow resin, which has an extremely long pot life. This makes it easier to mix without bubbles because you can go slow, which reduces the need for a pressure pot.
I think you might be able to save your castings by applying CA as you turn to fill the holes.
Hopefully I gave you some food for thought. Welcome to the forum, and best of luck with your projects!