Under Warranty has a 5% chance to proc Malfunction which lasts for about 1-2 seconds and causes TEDDY to change targets. Part of the perk mentions that TEDDY will crit on New Targets. TEDDY has base fire rate of 4 shots per second so its roughly 4-8 shots that will change targets randomly. 5% is low on paper but in practice Malfunction procs enough to be relevant.
For the duration of TEDDY, it will only crit each enemy once regardless of Target-switching or Malfunction reactivating. Tossing out a new TEDDY will allow it to crit each enemy once again. (Depression gang rise up!)
Crit is 2x damage. Only good if you need that damage to 1-2 shot basic husks due to the Crit limitation above.
There's some inconsistent/minor issue where TEDDY will stop firing for a split second before resuming. I'm currently assuming it has something to do with not being able to shoot/target Riot Huskies through their shield.
Summary: The perk is still useful if you plan on letting TEDDY absolutely massacre basic husks while you focus down on bigger husks because it's very unlikely to be stuck on a single Huskie/Smasher the entire time.
Lets discuss how some of you feel about my findings here. Feel free to test it yourself and give me corrections and more in-depth info to help with anyone who finds this post in the future.