I think there will enevitably be some tension whenever there is a slow down with one sub team.
For example, if it takes longer to make a CAD drawing of a subsystem then it does to make it, then of course manufacturing will get tense and slowed down, which leads to electronics and subsequently to programming. It's one huge domino set. You can't avoid it, it is almost a certainty that one part of the team will work slower than other sub-teams, leading to the others getting tense. Just accept that it will happen, and hopefully the other members of the team have the patience to deal with it when it happens.
(This is not just your team, this happens on all teams!)