If you come from an agency background then you are conditioned to only show perfect/close-to-perfect stuff to your clients because you don't want to leave poor first impressions. It's why there are multiple reviews and approvals before you show anything to the client. You want repeat business and a "failed" design would be treated as a strike against you.
When working closely with teams there is no need for that and you can bring in low fidelity artifacts like sketches for feedback without fear of the whole design group being judged. This is a big change to how designers generally work when they're employed by agencies. Unlike agencies, this is a safer environment (all things being equal) where imperfection might be rewarded by engineers, but unfortunately, the agency mindset is retained.
There definitely are ways to improve how we work together by playing some games, doing activities like assumption busting, diverge-converge design sketches etc. but the organization has to prioritize this mindset shift. The chance of it happening organically is limited.
There are issues the other way as well: developers are often conditioned to expect perfect designs for fear of "re-work". I find good software design, solid testing practices and EMs with an eye to ways of working (not just technical stuff) can help address that.
