Currently, checking the JQL advanced documentation in the Restricted words and characters we can see that there are some characters that need to be escaped for the JQL to correctly operate.

However, we've observed that some characters don't need to be escaped and it may cause problems for the customers if they're implementing their Jira Setup based on the documentation. The example below is for the character "/" that should be escaped to work correctly, but as we can see it didn't need to be escaped and only the period " . " was escapade.