2011 Ford Fiesta Jerky first gear when hot

[wagga_ria]

Hi All

Took over the 2011 Fiesta from my daughter who had bought a new car.

All good but I found that the transmission is a bit jerky from zero to the first gear, I assumed.
It is perfect when I initially started the car.
But after driving for about 30 minutes, and driving off from a stop, it sort of jerky to engage the next gear. It is okay after that. The rest of the gear change is smooth.
This happen all the time.
I'ved changed the transmission oil. Improve a bit initially, but revert back to the same problem.

What's your thought?