Hello,
i have a Jira instance where the the main menu entries "Dashboards", "Projects" and "Issues" dont open any more:

When you click them a small shadow appears below the menu entries are not displayed.
When leaving the page open like this for about 6 minutes suddenly some more data is loaded and the menus start responding.
The installed Jira Software Version is 7.5.3.
At first i only experienced this in chrome and switched to firefox but now i am experiencing this in both browsers.
This also happens when browsing in private.
Update:
i just encountered it on another instance with a similar history:
- Upgraded from Jira 7.1.9 to Jira 7.53
- Same 3rd Party Plugins: Email this Issue, Clone plus, Script Runner
kind regards
Jens