No that’s not the valve but let them send you a replacement anyways so you have one on hand if the current one stops working.
Bubbles coming up from the bottom is most likely just a bad seal.
Are you using the comfort pad under the bellows?
The bathmate entrance isn’t flat where it presses against you, it has that bend to help pump at a comfortable angle. I have found in many cases if the comfort pad is twisted at all, I have trouble getting vacuum to hold. Air slips in between the bellows and comfort pad if that makes sense. It is a slow leak tho, not like a bad seal on the skin which bubbles pretty fast.
Pumping without comfort pad and getting leak could just be saggy sack skin or too much pube stubble to make a good seal.
Hope this helps