Did you confirm fermentation was on going with a gravity reading or was you just observing the airlock activity?. If its the later, it could simply be de-gassing caused by siphoning.
If it is genuine fermentation then it should be finished by now, assuming it was in primary for any significant time. If it is just bottle/keg.
The temperature at which you dry hopped will dictate the length of time you can keep then hops in with the beer without off flavours. 11 days is longer than I would personally want, but then again I have had hop material in the fermenter for 4 weeks with no noticeable grass/veg flavour. If you at ferm temps like 18-19C then you won't have any problems.
Your more likely to get issues from oxidation or contamination if you rack again to another vessel. If it has finished or is close wait and untill the FG stablizes and then bottle/keg. If you think fermentation is still ongoing and isn't goning to stop soon, turn the temp down to the lower end of the fermentation range.
Either way I think your o.k.