As luck has it, I just opened a box and got a splice. so I came back to read here and saw your post. I look at the box.. and sure enough, it's not IJ. Checked the core on my old roll.. and it is IJ. A different supply person ordered this roll, and I guess he got the wrong one...
I just went and asked our usual purchaser if it was ok to use. He told me IJ is for digital, non IJ is for screen printing (We screenprint on it, so its fine!) he said the difference is Non IJ can be contaminated... It can have oil marks, splices, and other stuff in it, while IJ has stricter control on it.
I have no idea the price difference between the two - So it may, or may not be worth it for you to start bringing in IJ. Especially since you'd need to move to a different roll size. First time I've used non IJ, and I see theres a splice...thats going to be quite a bit of wasted material depending on where my cut ends up. I haven't tried printing on this one yet, but if I get the same thing you're getting, I have a feeling my boss won't be too happy throwing it all away ;p Luckly we need over half the roll for screen printing, so worst case I get a roll of IJ680 in, and keep this one for screen printing only.
Learn something new everyday it seems!
You can also see the difference in the spec sheet -
http://multimedia.3m.com/mws/media/...emovable-reflective-graphic-film-680cr-pb.pdf
http://multimedia.3m.com/mws/media/...ite-comply-reflective-slideable-removable.pdf
One mentions screen, the other mentions digital.. screen printing doesn't need to be as contaminate free as IJ does, paint tends to not blotch like what we see in your pictures.