This is caused by the following change in the latest (2.5.1-rc2) Mendix version:
- MXDN #4484 & #5494 & #5771: Disallow fields to be required when they are conditionally visible.
Until the version of the MxModelReflection module in the AppStore is updated, you can solve the errors by simply setting the
required property of those 4 fields to
This solved the problem. I was using Mendix 2.5.1rc1.
Did you also download the other mandatory component (Mx Model reflection) ?
Downloaded both components yesterday, have had no problems and no errors...