I received my attachments today. Some did not stick. Will this affect the final result of my Invisalign process?

I'm a 61 year old female who decided to jump in and go for the Invisalign treatment plan. The dentist opted to add the attachments on the third set of aligners. Some of the attachments did not stick to the teeth (4/19). Was this the technician's inexperience? And, will this prolong the process? The dentist decided that the missing attachments can be added during the refinement stage. Should I be concerned at this stage?