Toilet flush problem with water coming down pan after successful flush

[Kia606]

Our toilet which is a year old has begun to have a problem with its flush.
It flushes seemingly normally but then when the cistern has filled water comes down the pan for about 20-30 seconds then stops.
Hoping somebody has a fix for this

 

[ShaunCorbs]

Washer/ flapper or it’s overflowing / overfilling

What’s the water level like ?

 

[rpm]

If it is a new valve then some valves do do this, there is a name for them which I cant remember right now.

 

[ShaunCorbs]

Trap fill / primer if in usa

 

[rpm]

If it is a new valve then some valves do do this, there is a name for them which I cant remember right now.

Equilibrium fill valves dont shut off quickly like others do.

 

[Kia606]

Thank you everybody. I thought I would post pictures

of the level of water. It fills right up to the edge of the overflow pipe (?) escapes down there was some time then stabilises and stops

 

[Kia606]

Long and boring video of the flush but may be helpful to see