Hey Marc,
Since the timelines are using the core function the_excerpt(), all HTML gets stripped. This is actually default behavior, and not a bug with the plugin.
However, we’ve enabled an easy way to allow for HTML excerpts using a ‘Custom Excerpt’ field.
Take a look at the following documentation that we have setup:
https://www.wp-timelineexpress.com/documentation/enable-html-excerpts/
You’ll want to copy the code snippets provided in the docs into your themes functions.php. If you are not sure how to access and edit that file you can always use a third party plugin to add the code. We always recommend the following plugin, which works well: My Custom Functions
Once you add the code, you’ll see a new field appear on your announcements which does allow HTML to be entered in, and there is no limit to the excerpt length.
Give that a shot. That should help you in the right direction for what you are after.
Thanks,
Evan