LM2936M-3.3 Back biased by 5.5V via Schottky Diode

I have a legacy circuit that I have inherited, which consists of an LM2936M-3.3 which has 5.5V connected to the output via a Schottky diode.  The intent is to provide 3.3V from a 4V source to power up a circuit off a battery.  The circuit senses the Power On button for our product being pushed, and turns on a switching voltage regulator at 5.5V.  This then biases the 3.3V output of the regulator at about 5.3V, which then makes it compatible with the 5V inputs of the microcontroller.  I realize this is a bit of a Rube Goldberg contraption, but it is what I have to work with.  My real question is whether the 5.5V back bias will damage the regulator.  My read is that it will simply force the pass transistor off, turning off the regulator.  I have done some temperature measurements on the regulator with 3.3V out and 5.3V out, and the difference in case temperature is 0.5 deg C (24 vs 23.5).  We have been building this product for years with no failures, but I wanted to check with TI, just to be sure.