I will look into those. It very well may be the cheap bags. After trying the air bubble in water test, I removed the limes and let those two bags dry, and today I resealed them (with the limes). They are holding fine this time.
I put some of the limes into a third bag, and I noticed when pulling more plastic off the roll, that it is badly creased. So I made a point to put a non creased section of bag over the sealing area of the machine. I bet that was my issue yesterday, because I noticed creases yesterday, but I don’t think I paid much attention to whether they landed on the actual heating element.
Also, on some of them I did a double seal, and some I practiced with the in between seal setting, which is labeled “moist”. I don’t know how that settings is beneficial, but I can certainly see the advantage of using a double seal, in case one of them fails.