Why the document will be checked out by default when uploading it while having a custom content type

Question

I did the following:-

1. I created a new modern SharePoint page >> inside it i added a Button web part, as follow:-

2. The url for the button refers to the upload dialog for a document library, as follow @ /sites/POS-DocumentApprovalProcess/_layouts/Upload.aspx?List=%7b71b0e1f5-c427-44f8-9147-cb24d9df8dd8%7d

3. Now I click on the above Button >> Upload the document, as follow:-

4. Then i will be redirected to the edit properties form (since the document library has a custom content type with custom columns), as follow:-

5. After that i populated the required properties inside the edit form >> click on Save.

But the issue is that the uploaded document will be checked-out by default as follow:-

So can anyone advice why this is happening? why the document will be checked-out after been uploaded?

I checked the versioning settings for the document library and i have the following, so the document should not be checked-out by default when been uploaded and edited !!!:-

Answer 1

I followed the steps given by you, tried the same from my end and observed the same behavior in my SharePoint Online tenant.

I think this is some kind of bug or known issue (See below references).

My observations:

1. If custom content type has any required custom site columns then document is getting checked out automatically.
2. If custom content type does not have any custom site column or it does not have any required custom site columns then document is not getting checked out.

Suggestion: Create Online support ticket with Microsoft.

References:

1. How to Ensure that Users are Prompted for Document Metadata in Office 365 and SharePoint 2016 - See Bonus Tip section.
2. Don't Mess with Default Content Types in SharePoint - See So what’s the big deal? section