Gear shift issues

[Rolling Stone]

My bike will sometimes not shift past 2nd or 3rd when accelerating hard from standing (windgat weg trek by robot) Otherwise shifts no problem when I ride normally.  Anyone know what the problem can be?

 

[Kalahari Leeu]

 

[Rolling Stone]

 

[Rolling Stone]

 

[Gypsybaron]

 

[Triple Trompie]

 

[BiG DoM]

 

[Rolling Stone]

 

[Bokkeman]

 

[Rolling Stone]

 

[Gypsybaron]