Okay, so it is a matter of you not being able to get your engines to spool down from 300 kts?

That is weird.

What happens if you turn your AT off and just chop your throttles?  Are they still stuck?  Or is this just an AT thing?

If you can't get your speed reduced to below 300 knots, the last place you need to be is approaching a runway   :o  I suggest you fly around overhead until you run out of fuel and glide her in at a reasonable speed!