After upgrading from 2019.1.7 to 2019.4.8, some graphics on iOS are not displaying correctly

Our team has been using 2019.1.7 for development. Recently we decided to upgrade Unity. After upgrading to 2019.4.8 and we built the game and ran on iOS, we found that some of the graphics are not displaying correctly. It is perfect on Editor and Android. Below is one of the examples. About 30% of the graphics suffer from this problem and it appears to be random. (Not specific to some groups of graphics).

On Unity 2019.1.7 and 2020.1.2 it is perfectly fine. For some other reasons (bugs maybe), we cannot use both of these two versions now.

I have tried reimport all, upgrade from previous again using my backup, reset graphic settings, adjust the image individually, none of these work. Build from both Mac and Windows have the same problem.

Your help is much appreciated. Thanks.