Let me preface this by saying I am an amateur at powerapps, so please bear with me

I have a document library in SharePoint that we need to capture more info from users before a document can be sent for approval. I initially wanted to change the check in box that appears but that proved too difficult with SharePoint 365, so instead I designed the form by going to Integrate > Powerapps > Customize Forms

In power Apps, everything seems fine. The app checker doesn’t have any errors. In SharePoint though, when I hit the ‘Save’ button, I get ‘Network error when using patch function. The requested operation is invalid’. I didn’t write any patch functions as the fields were picked up by Power Apps.

Any tips or pointers at where I should be looking would be greatly received! Thanks In Advance!

I have tried stripping it right back so there is only one boolean control in the form and only one column in the library that it updates, but I still get the issue.

Image of issue