Warping when printing with Bambu PETG-HF and PLA as support

Hi all,

I'm trying to print this big piece for my thickness planer. I'm using Bambu PETG-HF as material for the body itself and the main support. For support interface I'm using Bambu PLA. It's printing just fine for the most part, however on the highlighted part the PETG-HF is starting to warp upwards while printing and I don't know why. The other side of the part which is the exact same is not affected. Could this be because of the Aux Fan or any other cooling setting?

Thanks for your input on this