When you look at the sun, the sun gets bigger. The animation for that isn't smooth. You can see how the shine around the sun gets a very high saturation. In the video, you can see this, but it's of very bad quality. So please create a new world and test it for yourself. Look from the side at the sun and move the camera in the direction of the sun.

Edit:
A better explanation, as some may not understand the issue: When you aim the camera from the side towards the sun, you can see how the colors change abruptly. It also looks like a cut, after the sun suddenly gets brighter. I have attached a second video where hopefully everyone can see what is meant.

No, the bug report MCPE-180015 does not describe the same issue.

Steps to Reproduce:

Look directly at the sun with the camera. Then, pan the camera to the left or right until the sun reaches its "standard size." Then slowly look back towards the sun. Like in the Video 0324(1).mp4

Observed Results:

At a certain point, the sun suddenly becomes significantly brighter, without a smooth transition. This makes it appear as if a second sun texture has been overlaid on the old one, causing the light rays to abruptly appear brighter without a transition, as the two textures overlap.

Expected Results:

The sun should have a smooth transition without sudden changes in color.

PS: If I had the choice, I would completely remove this feature (the sun enlarging) from the game. Because 1. It can be confusing, 2. It leads to errors like this, 3. Since this feature does not exist in Java, which makes the sky in general have a better effect.