How we can reproduce it:
1 Create new Unity project
2 Open Menu->Edit->Preferences and select "Cache Server(global)" tab
3 Make sure "Cache Server Default Mode" set to "Enabled" and set some wrong address for "Default IP address" - e.g. "loca"
4 Go to the right down corner and click on CacheServer status icon
Actual results: it is very laggy and window appears in 3-5 seconds and gives "RepaintAll" progress bar. Plus if you clear IP address field - the icon will still be yellow (should become grey)
Expected results: the icon should be grey and window should appear immediately
please see .gif attached in comments