i've found interesting acrobat "feature". I made up xfa form for submission with 2 required fields and 2 radiobuttons between them  with the hierarchy 
When i click on submit button only 1.textfield complain about missing value.2nd textfield is just ignored. When I move 2nd. textfield above radiobuttons in hierarchy tree everything works like charm. In Reader DC everything works as expected.Also when i change formproperties->Defaults->targetVersion from 10+ to 9.1+ even in acrobat validation works. Does someone find acceptableworkaroud for this feature?( solution is not, dont use acrobat version 10) .Thank you
Adobe Designer ES4 184.108.40.206...
Adobe Acrobat X Pro 10.1.16 - affected version
Disclaimer: I've reinstalled acrobat and have most updated patches