Unexpected behaviour with 'require' form rules

We are seeing unexpected behaviour with form rules on a legacy form. 

The form contains a form rule that makes several date fields required - I'll call them A, B and C.

The rule was set up so that the fields would be made required in the order A, B, C. However, the form generates 'the field X is required' messages in the order B, C, A. The behaviour doesn't change when we create 3 separate rules and change the order. It appears that the messages are generated in field ID order. Has anyone seen this behaviour?

Secondly, when we click OK after the 'the field X is required' messages, the date fields are being populated with the last date field entered into the form - e.g. if I populate field B and get a message to populate field A, field A is being populated with the value in field B when the form redisplays. It's very strange. Again, has anyone seen this behaviour?