The only time I ever had a problem with gummy needles was when I used it with Minkee backing. I possibly used too much, but I was trying to use it very sparingly, so I think it a little more likely that the spray reacted chemically with the polyester Minkee.
Maybe it would react with the poly in 80/20 batts, too? I think the only batts I've used so far with the 505 or June Tailor sprays were 100% cotton.
I wonder if anyone has had gummy needles when they used the spray sparingly on 100% cotton batt and fabric? Or did you get the gumminess when you were using a poly or poly blend batt or backing?
I just kept cleaning the needle with TriFlow lubricant and prayed for the end of that blasted Minkee quilt! Oh, I was so happy to get that thing done! :D