Safari - Phone numbers look different
Safari on mobile automatically recognizes phone numbers (or anything it thinks is a phone number) and wraps them inside an a tag, which is used to create a link. Because of this "phone number looking texts" can have different color on safari.
There are two solutions for this problem:
Disable this behavior entirely
According to the Safari HTML Reference you can disable this behavior using the following code:
<meta name="format-detection" content="telephone=no">
If you disable this but still want telephone links, you can still use the "tel" URI scheme.
Use a text layer with a custom link color
Create a text layer and at the layer window > design tab you can set a custom link color:
You should set this color to the same as the original text color, so even if Safari adds the link, the color will not change.