Hi Jesper,
I’m not aware of any conflicts. Usually when there is a delay, that means there is an additional task running with the request, stuff like update checks or some maintenance related code. I don’t think Ninja Forms is touching the search query itself, it might be just triggering something on accident or another plugin triggers something when Ninja Forms is active, it could be anything.
I have a few tips to debug this:
– First, temporarily deactivate all plugins except for search plugin and the Ninja Forms to see if the conflict persist. I suspect it may go away. In that case try reactivating them one-by one to see how it changes.
– If it’s completely random, then the most likely cause is low memory. It’s super rare, but explains the problem. After a certain number of plugins active the PHP process could run out of memory and so it “slows” down to manage it, increasing the memory limit usually helps. You can do it on the server side or via wp-config.php if it’s allowed.
I recommend starting from 1024M and if that solves the issue, then gradually going down.
– If no luck with the memory, then there is still hope via enabling the custom ajax handler. That will try to bybass some unneccessary loading, and in many cases improves the performance greatly.