[tl;dr at the bottom]
(Project Team Group Chat)
dev: @Desing team, i have a question, there's a required field missing in you design, can i go to your desktop to get an quick answer/explanation about that?
design team:....
dev: hello..?
PM: [writes a huge text to tell me that i can not interrupt them even if its a blocker and that we (dev team) shoul write them down and tell them only once a day in the scrum meeting]
dev: uuumm ok

-next day-
dev: so about that field, why did you...
Client: WHAT? There's a problem with the design!? oh boy, lets re-check every view right now with the whole team!
(it took like 2 hours, the field was missing just because they forgot that feature)
PM: okay, @DesingTeam, answer any questions from developers when they ask you...

tl;dr
we spent almost two hours with the client just because desing team didn't want to answer me a little question