Hi there,
I think there is also an issue with the ACF Group feature in v4.1.1.
Perhaps this is similar to the ACF Repeater issue as the ACF Group feature works fine when I downgrade to v4.0.2.
I ran this simple test, but the loop did not run and return the title:
<!--Banner Group-->
<Loop acf_group="sim_group_test" from="options">
<!--Banner Title-->
<Field title />
</Loop>
@benjamin can you replicate this?
Thanks.