This keeps happening and has done so for awhile. But it's always fixed on a reload.
I always disable elvuis bag btw. but I download bugsack to see what the issue/lua error was.
Basically, whenever I vendor/mail/bank/trade items, the empty space which is created from these items moving out of my bag will stay as an empty space. Even if i close or open my bag, there is empty space, if I already have other items still in my bag they will clip out of the frame.
Got this:

AdiBags\widgets\ContainerFrame.lua:998: Action[SetPoint] failed because[Cannot anchor to a region dependent on it]: attempted from: AdiBagsSection8:SetPoint.
[string "=[C]"]: in function SetPoint' [string "@AdiBags\widgets\ContainerFrame.lua"]:998: in function LayoutSections'
[string "@AdiBags\widgets\ContainerFrame.lua"]:1069: in function <AdiBags\widgets\ContainerFrame.lua:1043>
[string "=(tail call)"]: ?
[string "@AdiBags\widgets\ContainerFrame.lua"]:396: in function ?' [string "@ElvUI\Libraries\Ace3\CallbackHandler-1.0\CallbackHandler-1.0-7.lua"]:119: in function <...ies\Ace3\CallbackHandler-1.0\CallbackHandler-1.0.lua:119> [string "=[C]"]: ? [string "@ElvUI\Libraries\Ace3\CallbackHandler-1.0\CallbackHandler-1.0-7.lua"]:29: in function <...ies\Ace3\CallbackHandler-1.0\CallbackHandler-1.0.lua:25> [string "@ElvUI\Libraries\Ace3\CallbackHandler-1.0\CallbackHandler-1.0-7.lua"]:64: in function SendMessage'
[string "@AdiBags\core\Core.lua"]:349: in function `?'
[string "@ElvUI\Libraries\Ace3\CallbackHandler-1.0\CallbackHandler-1.0-7.lua"]:119: in function <...ies\Ace3\CallbackHandler-1.0\CallbackHandler-1.0.lua:119>
[string "=[C]"]: ?
[string "@ElvUI\Libraries\Ace3\CallbackHandler-1.0\CallbackHandler-1.0-7.lua"]:29: in function <...ies\Ace3\CallbackHandler-1.0\CallbackHandler-1.0.lua:25>
[string "@ElvUI\Libraries\Ace3\CallbackHandler-1.0\CallbackHandler-1.0-7.lua"]:64: in function <...ies\Ace3\CallbackHandler-1.0\CallbackHandler-1.0.lua:59>
[string "=(tail call)"]: ?

https://gyazo.com/2f410c518c2a6c25eb8d321890d79c56 here's a screenshot of what I mean, i don't know what causes it but it's been doing it for a long time now. reloading fixes it though. but why does it keep doing it.