As far as I have been able to tell, this isn't actually a "problem." I've had guild quests that stop counting after 10, but when you open your quest log and go to the guild quests tab, they specifically say (Guild)Suppression Orders: Blah Blah Blah < X/10 > where X is the number of times you've completed it already. Once you finish those 10 turn ins, the quest is apparantly supposed to disappear entirely. The only guild quests that stay in your log no matter how many times you turn it in are the ones that say (Guild) Suppression Orders: Blah Blah Bla> < X/Unlimited >. Examples provided below.

Oh interesting. I didn't even see that there but now that you mention it I can see that now. Hmm well that is rather frustrating.

True Emirie. That is actually a bug also though. GM are going to fix it. All of the quests are meant to be repeatable "unlimited". Least thats what GM are telling me.

The "10" is meant to be how many times you can stack it. Not total completions.

I ran in to it last night with Guild Suppression Orders: Ossuguns (in Thrallhold - Three Spires Tower). It is no longer in my logs but I didn't look to see if it was x/10 or x/Unlimited.