During an upgrade from a CRM 2011 system to CRM 2015, testers reported that some subgrids in the system were occasionally having strange visual errors where the buttons were being pushed down into where the field labels were displayed, and if the subgrid was in a labelled section the section name would also be pushed down into the field labels.
In investigating this issue, this occurred on subgrids inside tabs/sections that were hidden in the onload event, and then depending on a change of field value to then display the section again. However, showing/hiding a tab/section did not cause this after the form had loaded, only hiding during the onload event caused the issue. This also occurred in 2013 systems when tested.
My solution for this issue was to inverse the current setup of the form, instead of the tabs being visible by default and then, hidden in the onload event depending on field values, hide the tabs by default and then show them based on field values.