Voltage regulator output too high
The L78LXX requires 2 volts difference between input and output.  5V in to a 3.3V regulator is outside of the specifications.  It's anybody's guess what it will do.
The MT1117A datasheet specifies a tantalum capacitor on the output.  If you use anything else, there's a good chance it will oscillate.  The output voltage may appear to be too high or too low when it oscillates - it depends on what your voltmeter does when hit with something it doesn't expect.
The LM2931 requires a 100µF capacitor to be stable - your 10µF won't be enough.  On top of that, the LM2931 datasheet says that it requires that the capacitor have a specific equivalent series resistance (ESR) to be stable.  If your capacitor is too small or if it doesn't meet the ESR requirements given in figure 34 on page 10, then it will oscillate - that causes the same wonky voltages readings that you would see if the MT1117 were oscillating.
Check that you have the regulator connected the right way around.  It was really easy to connect regulators in TO-92 or TO-220 housings backwards.  It's harder with SMD components, but it still happens.
Outside of those causes, you should check to see if your voltmeter is working correctly.  Many voltmeters show incorrect voltages when the battery is weak.

Check things in this order:

Check the battery in the voltmeter - or check if it reads a known voltage correctly.
Make sure the regulator is wired correctly.
Double check the output capacitor type and value.
Hook the output to an oscilloscope and see if it is oscillating.