Instant regen that high does sound a bit excessive, but the mod scales with CA level and that high a level of regen sounds like it would have to be a fairly high level ca. Regardless, if that's how it works there isn't much you can do about it except to see how far you can push it
I'm pretty sure I figured out why its so high. The wiki says that it regens 5% + another 5% per level, but I think someone must have left out the zero or something because its defintely 50% + 50% per level. So at a CA level of 40 it will instantly regen 20 seconds