My hood doesn't "pop" up either, but at least it releases. I had a period when it wouldn't release unless I was pulling up the hood while pulling the release lever at the same time. It's hard to be in two places at once, but that Extenz really does a great job...
I was afraid to adjust my hood bumpers much higher because it looked like my hood was starting to bend up on the corners. I don't know why Isuzu didn't include a spring like my other cars use.