After a bit more reading I found that the TL0xx series opamps DO suffer phase reversal if the common-mode input gets too close to the negative rail. So if you are using a 9V supply and Vref=4.5V then your signal is swinging down to 3.5V and up to 5.5V. That 3.5V downward swing might be enough to cause problems in UGFB configuration. According to the datasheet the max output voltage for a 9V supply is about 6V P-P (not very good!) and in UGFB configuration the common-mode input voltage is (ideally) equal to the output voltage (meaning since the . If the output clips negative and you get phase reversal from too low CM input, this will typically causes the signal to slam into the positive rail and either latch up or recover (the TL0xx stuff is supposed to be latch-up free though, which they are IME). Sounds like you might be experiencing this, I don't think I have ever though..
I believe that is exactly what I was doing. I remember I had the Op Amp biased directly from the transistor, most likely a 10k off the collector. The first one was probably getting full swing, and the second one I blew must've still been getting enough voltage to blow. Could've been a Bazz Fuss for all I remember. I've used 358's and 2904's like that with no problems, but I'm guessing they are less problematic since the outputs can swing all the way to ground. Or are they prone to this issue as well? (LM358 (2904) has definitely become my favorite little op amp).