In the page https://confluence.atlassian.com/adminjiraserver/upgrading-jira-server-manual-938846939.html

 Has the following recommendation:

Install the database driver

If you're using an Oracle or MySQL database, download a new JDBC driver. For other databases, you can omit this step.
If the driver is up to date, you can also copy it from your previous version.

1. Download one of the following drivers:

• • Oracle: JDBC driver 12.2.0.1.
  • MySQL: the latest JDBC driver.

1. Place it in <installation-directory>/lib.

 However Jira can't currently use the latest mysql jdbc driver, which is version 8.  Instead Jira needs to be using the latest 5.1 driver as explained in both the supported platforms doc and the Connecting Jira to mysql documentation.  

When users follow this guide and install the 8.0 version, Jira can't correctly connect to these database types.