I'm quite sure this worked a few weeks ago. When you add a subgrid to a form, and then add the power apps grid control, and set it to enable edit in the main grid, it appears as though it worked. However, when you enter information or change an option from yes to no, and then navigate away from the record, your changes are not saved. The old editable grid works, however the new power apps grid control is not working in this context. Does anyone else see similar behaviour?
There are no errors or warnings and it appears to save, but when you navigate back, the update is not saved. The control seems to work fine on views, just not on forms with related data.