Hosted on ERPNext Cloud
ERPNext: v10.1.40 (master)
Frappe Framework: v10.1.37 (master)
After entering the 1st row, the next rows becomes like the one in the screenshot below:

This happens on Chrome and Edge for sure.
Tested in Environment
ERPNext: v10.1.61 (master)
Frappe Framework: v10.1.54 (master)
It is working Fine , no Issue reported.

This is still occurring for me...

ERPNext: v10.1.58 (master)
Frappe Framework: v10.1.51 (master)
It seems it is a customized SO Item table , as the column names are Supplier Number, Packing Unit etc..
Yes, it clearly is. But why does it do this? Seems a bug to me?
@heatherpotter It's advisable to add only 4 to maximum 5 fields in child table's grid view.
@shreyashah115 Well, that's confusing. Why is it even possible if not advisable? In addition, why doesn't ERPNext take full advantage of edge to edge browser window. Makes no sense.
We will have to live with the bug as we have to have the form display exactly those 7 columns when entering the order. Our orders have 50-100 line items that we enter and it must go quickly - we don't have time to click the arrow and so on.
Most helpful comment
This happens on Chrome and Edge for sure.