Misplaced Downshift 2009 Legacy

[palfer]

My 09' Legacy has 97K miles.  I change the fluids at the appropriate intervals but recently the transmission has been downshifting inappropriately.  Doesn't happen on every trip but occurs when I'm on a flat freeway driving 75-80mph.  I'll be cruising along at about 3K rpm's and out of nowhere it will momentarily downshift.  The rpm's jump to 4.5K and out of reaction I let off the gas pedal and it will immediately upshift back to 4th gear.

The whole episode lasts about 3 seconds but its alarming as its completely unexpected based on how I'm driving.  It doesn't trigger a check engine light but I pulled the codes anyway and I'm getting a C0045 and C0071