UCC28780: Could not get a stable burst close to transition from ABM to AAM

Hello,

Close to transition from ABM to AAM, the time between each burst is not constant, leading to a "virtual" miss of gating the high side transistor. See picture below:

• CH1 : Vgs of SR mosfet
• CH2 : Vgs of high-side mosfet
• CH3 : Current in primary of transformer
• CH4 : Voltage at switching node (primary)

Here is another one at higher load closer to AAM:

(CH2 is not connected that time)

Maybe transitioning sooner to AAM can solve the issue?

Thanks for all the help you can bring.