Studio Display Fan & Brightness Problems

I've owned my Studio Display for about three years now, and unfortunately, I can't say it's been trouble-free. 

First, I had a pink horizontal line in the middle of my screen that was only visible against light backgrounds. After taking it to Apple for its first repair attempt, they told me they were able to reproduce the problem with another Studio Display and that it was therefore definitely a software bug that would eventually be fixed. When nothing had happened after two or three months, I took it back to the Apple Store, and there, just before the warranty expired, they repaired it again and replaced the panel. At least that part has worked since then. 

For about a year now, I've had the problem that the brightness of my display suddenly dims and the fans run at 100%, even though the display is cold. I've also had days where it constantly switches back and forth: brightness down and fans on. Two minutes later, it's quiet and bright again. Two minutes later, the fans are on again and the brightness is down again. I've also tried blowing into the display from below with an air gun, and occasionally it seemed to fix the problem for the day. Has anyone else experienced this issue?