If you got an addon named RT_Grid, or similar: yes
I bet so.
Search the addon, navigate to the addon comments page at www.esoui.com,and most probably someone already posted a fix there. Else ask the dev to fix it please.

ZOs changed all TopLevelControls to be parented only to the GuiRoot control. Should have always been that way but was forced with high Isle now.
So any code that forces the control to get another patent causes this now.

Find the addon, find the TopLevelControl in it, find where there is TopLevelControlName:SetParent(SomethingElseThanGuiRoot) and comment this line by adding - - up in front. Easiest fix but might break the addon and could need further changes to work properly.