Pluggin filter posts randomnly with only half my keywords list

Hi!

I have a list of about 680 keywords, I tested with a dummy post that contained all of the keywords, when looking at the category lists it created in the post, it only contained half of the keywords, random ones were missing, appellations were correct, in the keyword, list.

I had 344 keywords on the total of 680.

Is there a maximum amount of keywords that can be processed. What should I try to remedy to this issue?

Otherwise great plugin.. Thanks for your help!