Not sure if this is a repost, but as the title suggests, whenever you update episerver forms, the forms.config gets overwritten, consequently reverting all the configurations to default.
Is there a way to prevent this?
Source control all config files and review before committing an upgrade.
If Epi doesn't plan to make more fine grained upgrade transforms instead of just overwriting with a new file you could add your stuff to a config-transform that you control and apply it on Epi's file.
I second Johan's suggestion, anything you're changing from the out of the box config or implementation should always be source controlled and reviewed when upgrading.
Second Johans suggestion as well.Very strange that we have to edit files in their package to make our on config, the need to change that.