Hi Everyone,
I am very sorry for the inconvenience this is bringing to all of you! I am trying to resolve this as soon as possible. Thanks a lot @Predeactor for the great workaround described.
I will document any progress regarding a the development of a solution here: https://github.com/Foundry376/Mailspring/issues/2373
I hope that I can find a solution fast in order to cut a bugfix release for this.