Big problems Shifting into 4th

Whitemtl370

Ill get Straight to it, at wot my 1-2-3 gear changes are great, no problems, however shifting into 4th above 7k rpm in 3rd is... Well, odd. Half the time the clutch grabs 4th ang goes. However, the other half of the time, the car reacts as if i shifted into 2nd from the redline in 3rd ( banging off the limiter, car slows down FAST). This has happened to me atleast 5 times, and yes i shifted into 4th as the indictor on the speedo confirms. Last night i attempted to granny shift from 3rd to 4th at 7000 rpm, i dissengaged the throttle, pushed the clutch to the floor, movedthe gearshift at a casual pace securely into 4th, and the instant i let off the clutch the car repeatedly bounced off the redline as if were in 2nd, i looked at the dash, the car was indeed in 4th...

Any help is appreciated