I have a Custom HTML tag in Google Tag Manager that is actually very simple. It consists of the following code (a GTM Macro):
{{html generator}}
This tag is only fired on the Thank-you page on my website. This firing rule works fine, as I'm using it for a couple of other tags.
The Custom Javascript {{html generator}} macro is more complex. The macro generates one or two image pixels in HTML. Due to the complexity of the image pixels, I cannot use the Custom Image tag. :
<img src="url1/?query1" width="1" height="1" /><img src="url2/?query2" width="1" height="1" />
Via console.log I have verified that the macro Javascript function generates the correct string.
Why is the HTML not executed? I don't believe it is a caching issue as the query parameters always have a different outcome. I believe it is a timing issue.