@MisterKelly, thanks for giving a try and help narrowing down the issue. You can indeed leave the parameter to "0", it simply means that fuzzy mode won't be enabled when doing a search. I'd be interested to know if this definitely fixes the problem for you, or if it comes back, so if it does please let us know.
@naviji, I wonder if there are some issues with the Spellfix extensions? In my case, I managed to corrupt my database while I was investigating this issue by creating many notes. I don't know for sure if it was due to the extension but I thought it could be related. Do you have any idea about all this? In any case, let's wait and see if we can find a solution, otherwise we'll have to consider removing it as stability and performance is crucial.