Seeing Unexpected token '=' only on Mobile Safari UI/WKWebView

Hi, 

I have installed google tag manager snippet of code, pasting it in my website's and . The only change I made to the snippets was converting the quote marks from ` to ". It seems to work fine on all our platforms, but i'm constantly seeing the same error show up for users who are accessing our site via Mobile Safari UI/WKWebView. Can you please advice me on why this might be happening and how I could fix it?

Thank you. 

Seeing Unexpected token '=' only on Mobile Safari UI/WKWebView
 
 
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