I believe the feature request to improve this in web-vault and desktop app is Unsaved changes are lost when move to another item
You can use one of your 20 votes to increase priority of feature and make it more likely to be implemented sooner.
Currently, there are other prioritized features, as shown in upcoming roadmap (Bitwarden Roadmap) and list of all features by votes (Feature Requests - Bitwarden Community Forums)
Bitwarden team is going through a large backlog of features, so it is hard to say when they will get around to this, but it is at least acknowledged: