2006 VW Jetta going into "limp mode"

I’m hoping someone has experienced this before. Twice now, my 2006 VW Jetta has gone into “limp mode”–RPMs rev like mad but I get very little power, won’t go into overdrive. Had to get it home both times by using the Tiptronic. The first time it happened, we were driving through The Poconos on a nice day. Shut the car off & restarted it with no problem. The 2nd time was during an intensely hot day & torrential rainstorm in MD. The car sat for 2 days before going back to normal.

Is this normal behavior for a VW? And what makes it go into limp mode? I can understand it happening during the rainstorm but on a nice day of normal driving? Very weird.

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