Tested on enwiki (wmf.17)
On 'Recent changes' select 'Show last 500 changes in last 30 days' and 'Very likely have problems' and 'Logged actions' ('Logged actions', Likely bad faith'). The 'No results found...' message takes a very long time to be displayed - 4.5 min to 26 min
- other conflicting filters, e.g. 'Unregistered' and 'Newcomers', don't take that much time to load.