Hard to tell for the bubbling because I went with an xacto knife and cut out the middle of the inserts. I did one large decal for the indian's face and that one has no bubbling so I'd say it's only over the black print.
Yes, I did some filling already, but I'll see how flat it is after I wet sand it and will refill if needed. I'm now almost out of my red mix so I hope I don't have any issues this time around. I'm using Createx and I've been sporadically working on this playfield for over a year, and I had to refill the paint with some water to get it to a correct viscosity.
I did the same with the blue with no problems though, so I think it probably is because it didn't cure long enough...