I couldn't find anyone else with this exact problem, so it may be strangely unique to me. Just in case, I'm posting my solution. FYI, I'm using version 2.2.6.
Problem: You create a custom multipart (HTML/Text) notification and notice the full HTML message is not sent.
Symptoms: After determining it's not a Smarty problem, you make small changes to the code and realize that your changes make a difference, but only in breaking the code in new places. No pattern emerges.
After hours of experiments and pulling your hair out (hopefully you found this post first), you stumble upon the realization that the text version is somehow causing the problem. When you take the text version out, everything gets sent fine. You also test using a built-in example text template, but the problem remains.
Solution 1: You could just remove the text version and only use HTML, but it's less likely your message will get through spam filters. Also, I still run into mobile phones that only accept plain text.
Solution 2 (better): I've identified that this is somehow a mail() problem. When I switched to the Swift Mailer module, everything worked fine.
Hope this helps someone.
Problem: You create a custom multipart (HTML/Text) notification and notice the full HTML message is not sent.
Symptoms: After determining it's not a Smarty problem, you make small changes to the code and realize that your changes make a difference, but only in breaking the code in new places. No pattern emerges.
After hours of experiments and pulling your hair out (hopefully you found this post first), you stumble upon the realization that the text version is somehow causing the problem. When you take the text version out, everything gets sent fine. You also test using a built-in example text template, but the problem remains.
Solution 1: You could just remove the text version and only use HTML, but it's less likely your message will get through spam filters. Also, I still run into mobile phones that only accept plain text.
Solution 2 (better): I've identified that this is somehow a mail() problem. When I switched to the Swift Mailer module, everything worked fine.
Hope this helps someone.