Yes my Aura does the same, sometimes several times a day and quite often daily.
Does yours go for a soft power down and power up where it only loses picture for a matter of seconds,
when mine does this any recordings taking place carry on recording even though the LED has turned blue.
Or does your go for a full power down and full power up with the Humax logo followed by
the Android start up screen followed by the white rotating circle for a few minutes and then goes to live TV.
Any recordings taking place whilst it does this will have been interrupted but after coming back on the recordings should start again.
In the recordings list you will see the broken recording sign, but it should play normally (until the point when the Aura decided to restart)
but will immediately start the second recording performed after the restart, so you will miss a couple of minutes.
When the Aura decides it is having a bad day and has powered down a few times and I get annoyed I hold the power button down for a few seconds
and then press OK on the power off splash screen. I then leave the Aura alone for over ten minutes (the LED should be completely off, if no recordings
are taking place of course) and then power up, this usually sorts the Aura out for a couple of days or more.
Other things you could try are a Freeview reset, which can be accessed under Freeview Play Preferences in Settings.
Or if the Aura is being particularly cantankerous do a Factory Reset.
Be aware of what will happen when you attempt either or both of the resets, prepare yourself beforehand.
Not sure why it does this, just the magic of owning an Aura.
I have often thought of taking the cover off and seeing if it full of dust which may be causing it to over heat.
But haven't done so.
My Aura is now over three years old, what age is yours.