We found that, in the sandbox, we found that we are seeing this issue after configuring 109 attributes, and in prod, we are seeing it after configuring 120 attributes.
Steps to Reproduce:
1. Create close to 200 attributes on the custom subobject under project object
2. These attributes is a combination of lookups, Large Strings, booleans, attachments etc...
3. Attempt to configure these attributes on the Details Flyout.
4. After about 100 or so attributes on the details you will observe that attributes start overlaying at the bottom.
Expected Results: Since 200 attribute is the limit for the Details Flyout it should allow to add them.
Actual Results: It is overlaying attributes after putting 100 or so attributes.
Release : 16.0.3
DE69138, Fixed in 16.1.2.