I ended up getting a teleport tower lvl 6. It said it had recharge time of 0 seconds, but it was actually 6, like lvl 5. I'd post a pic of the error if I could, but I can't put up a pic.

I've had this happen to me too, but I thought it was because I was using Faster Towers.

I should've taken a screeny.

I took a screenshot, but can't upload it here because we can't do that... yet.

you can email it to ryanritten@gmail.com

the numbers i recorded looked like this.

normal time without "faster towers"

lvl 1 - 34 seconds
lvl 2 - 29 seconds
lvl 3 - 23 seconds
lvl 4 - 17 seconds
lvl 5 - 12 seconds
lvl 6 - 6 seconds

with full faster towers

lvl 1 - 23 seconds
lvl 2 - 23 seconds (NO CHANGE)
lvl 3 - 17 seconds
lvl 4 - 12 seconds
lvl 5 - 6 seconds
lvl 6 - 6 seconds (NO CHANGE)

with full faster towers at lvl 5 it does state that the change will be -6 bringing it to 0 but the actual time seems to still be around 6 seconds.

i would suggest to you again that the teleport tower has the same "bug" that the rapid tower has where a specific set of numbers repeats instead of calculated numbers.