Chime Rings every 20 seconds or so

Just installed the 1080-P doorbell. All voltage checks out, used the jumper per the instructions but the thing rings non-stop.

It definitely sounds like the jumper / bypass element is wrong, and you are just shorting the chime circuit out. I haven’t used this particular doorbell, but I had similar issues with another brand when I installed it. Eventually got the right setting on the doorbell and location on the switch, but these aren’t the most intuitive things to get setup.