opinions on my canning situation please

I made some apple pie filling yesterday, and canned 12 quarts. I used cornstarch as the thickener. Even tho I stirred the jars before processing them (water bath canning) I can see some little air bubbles in the jars. By the way this is my 2nd time canning apple pie filling. This time I did have to reprocess 3 jars because they did not seal. Process time I did was 25 min.
I'm guessing they did not seal because I didn't put the bands on tight enough, or I didn't leave enough headspace. Also when I was taking the bands off of them today I saw that several jars had pie filling around the top. I'm guessing that it was pushed out during processing. All the jars are sealed, the lids are down.
I'm writing all this to get your opinions/ experiences on this. I'm really not worried about what I have here for the following reasons.
1. I keep stuff clean.
2. As I said the lids are down.
3. I understand that bacteria doesn't grow in a high sugar environment.
4. I used some lemon juice in the recipe for some extra acid that also makes life difficult for bacteria.
Hope thats enough info for you to give me an opinion.
Thanks.

There is not much danger with high sugar/high acid products, but I would re-process these. Remove the lids, clean the rims, maybe take a little out to make more headspace, and then run them again. Little bits of food caught under the lids is enough to allow bacteria to get in and they can spoil even sugary food at the surface.

Thanks Mr. D. I plan to use up the jars where some came out first, and that will be in the next couple weeks.I also left myself a note in the recipe to leave extra head space.