I have been off for a while so just noticed your post without any replies.

If the bowl is not completely full of liquid the flow can cause bubbles.

Since air is much thinner than gasoline you can get bubbles without any noticeable leaks. My advise is to tighten connections and maybe put a bit of grease on connections that you think might be drawing in air to see if the bubbles are eliminated or reduced.

If none of that changes anything wait a little longer for the real source of the problem to surface. Keep your AAA or Hagerty towing up to date.

If the fuel line goes to the top of the tank fill the tank very near capacity then watch the glass. The pipe inside the tank may be cracked enough to let a small amount of air in but not enough to affect engine performance. This suggestion wont work if the fuel connection is at the bottom of the tank.

Tony