The first image is from the reminder email and the second is from Scoutbook. Notice the reminder email is showing the markup and Scoutbook is rendering is properly.
I did have another event show correctly both in email and Scoutbook.
Do you have some kind of Security set up on the Email Client that disables coding?
No. I had one outing work properly. The one that worked properly was sent before the one that didn’t. A reminder for the one that didn’t was set before that and didn’t work. So I had this behavior: test markup activity worked, real world activity A reminder didn’t work, real world activity B worked, real wold activity A reminder didn’t work. The properly rendered emails worked on 2 different outlooks systems and my iPhone. The improperly rendered emails didn’t work in outlook on my PCs and my iPhone.