Validation report error that i don't understand

[xyu]

Hi, i've tried searching the forums for this error but was unsuccessful so if there is another link explaining it then i'm sorry.

When i create a Witch hunter army roster I get no validation errors. I then save the roster close down AB. Open AB and load my roster and it comes back with this error:

<!> Only one WH HQ unit allowed when taken as allies ** Must take 2 parent race troop units.

In my roster I'm using 2 HQs as allowed and 4 troop choices. None of my other choices break any rules. This only errors when i save and reopen.

If i delete 1 HQ the error changes to "Must take a parent race HQ unit** must take 2 parent race troop units"

All of my army are sisters of battle including the HQs.

Thanks for your help.