In Incidents, Changes, and Problems, the words / Texts in pointed brackets <...> are deleted. The same with direct Inputs (text box), texts by MailEater or Webservice. This behavior is noted after 17.4 RU2, and an HTML description was introduced in it.
Steps:
1. Edit the respective HTMPL form, making the description field a regular textbox, removing HTML content in the pdm_macro.
2. Create a ticket and in the description, enter text as <testing> and save.
3. Once saved, the value is blank.
CA Service Desk Manager 17.4 RU4
The fix for the reported behavior will be part of 17.4 RU5.