loads of LUA errors

[Karkov]

Hi all.
I'm suddenly experiecing a massive amount of LUA errors, linked to addons that are up to date, such as gatherer. One of these is:

39x Gatherer\GatherTooltip.lua:77: Attempt to access forbidden object from code tainted by an AddOn
[C]: in function `NumLines'
Gatherer\GatherTooltip.lua:77: in function <Gatherer\GatherTooltip.lua:76>
[C]: in function `SetUnitAura'
[string "*:OnEnter"]:2: in function <[string "*:OnEnter"]:1>

Locals:

Another example linked to Bartender is:

1566x ...er4\libs\LibActionButton-1.0\LibActionButton-1.0-69.lua:743: Attempt to access forbidden object from code tainted by an AddOn
[C]: in function `GetOwner'
...er4\libs\LibActionButton-1.0\LibActionButton-1.0-69.lua:743: in function <...er4\libs\LibActionButton-1.0\LibActionButton-1.0.lua:703>

Locals:

Yet another is:

7x ...aceMythicPlusProgress\MythicPlusProgress-0.3e for Patch 7.1.0.lua:214: attempt to index a nil value
...aceMythicPlusProgress\MythicPlusProgress-0.3e for Patch 7.1.0.lua:214: in function <...aceMythicPlusProgress\MythicPlusProgress.lua:212>
...aceMythicPlusProgress\MythicPlusProgress-0.3e for Patch 7.1.0.lua:220: in function <...aceMythicPlusProgress\MythicPlusProgress.lua:217>
...aceMythicPlusProgress\MythicPlusProgress-0.3e for Patch 7.1.0.lua:567: in function <...aceMythicPlusProgress\MythicPlusProgress.lua:557>
...aceMythicPlusProgress\MythicPlusProgress-0.3e for Patch 7.1.0.lua:712: in function <...aceMythicPlusProgress\MythicPlusProgress.lua:708>

Locals:
(*temporary) = <function> defined =[C]:-1
(*temporary) = nil
(*temporary) = 3
(*temporary) = "attempt to index a nil value"
simulationCurrent = 28
strtrim = <function> defined =[C]:-1
getProgressInfo = <function> defined @MythicPlusProgress\MythicPlusProgress.lua:188

Obviously, since I have a lot of addons, and have spent a lot of time setting it up, I'm hoping for an easy fix. Can someone help?

I should mention they only ever show up in instances