פירוש על עבודה זרה 63:9

There are two solutions to the contradiction between these two baraitot. According to the first solution, the earlier baraita meant that the other sages disagree with Rabban Gamaliel, but Rabban Gamaliel’s own son did agree with him, and that is what is meant by the above baraita.
The other solution is that there are two different rabbis who transmit this incident—each with almost the same name, but different. The first is Shimon ben Gudda with an aleph at the end and the second is Shimon ben Gudda’ with an ayin at the end. I’ll admit that this is a strained solution, but nevertheless, Jews probably did pronounce the ayin and the aleph different.