Gaussian Blur Illustrator has different effect when use with multiply blending mode

Hi, I have a problem with my illustrator CC 2025. I try to use the gaussian effect on any vector object and when I apply multiply and adjusting the transparency, the effect changes.

See the difference with the first image and the last? Once I play around with the transparency of multiply blending, the gaussian changes effect differently even I change back to the same setting as initial starting. 

Does anyone has this problem and solved them?