That sounds like a bug in the expression evaluator. For a better workaround, instead of checking “Use Managed Compatibility Mode”, check “Use the legacy C# and VB expression evaluators”. This should enable you to continue using Edit and Continue as well as other features added within the last few releases.
In terms of the “Internal error in expression evaluator”, can you please open an issue by going to Help -> Send Feedback -> Report a problem? That will help us fix the problem in future releases.