Mine's been dis-connected for years now, but I have it wired so I can control it with a switch..... use it as an exhaust brake (of sorts).. going down hills, towing..... or use it to speed up a warm up, at idle, on a cold, cold start.
JMO but it shouldn't be able come on randomly though.... it puts back pressure against the turbo.. and can cause it to overheat and you'd feel a serious power loss under throttle demands... if it's un-controlled. Smoke too.(an EGT gauge will reflect the temp increase)
Joe