double digest weirdness

[palindrometric]

Hey....I've been having issues with a double digest/insertion and wanted some feedback. Here goes:

Enzymes: PinAI and XhoI (both NEB)

Used NEB buffer "B" from table

After PCR, insert was PCR purified with Invitrogen PCR Gel kit
After digestion w/enzymes, insert and vector were cleaned with Invitrogen PCR clean-up kit

Plates and growth:
1. bugs only: no growth
2. bugs + vector without phosphatase treatment: lots of growth; lawn
3. bugs + vector w/phosphatase treatment + insert: intermediate growth
4. bugs + vector + insert w/phopahatase treatment: intermediate growth (about same as #3).

We have been unable to get a vector with insert after mini and test cut. Phosphatase treatment is new, but I don't get why there was (1) still a lot of growth and (2) ANY growth with insert treated