No it shouldn’t be related to my package,
What version do you have of PlotlyJS installed in the notebook above where you had the error? (You can check the version by clicking on the tick next to the name).
It might be (if this was not a new notebook but one you have been using for a while) that the version of PlotlyJS was fixed to the one that was available when you first created the notebook.
This is the default behavior with the new Pluto pkgmanager (only update package after manual trigger by the user)
You can update packages by clicking on the tick and pressing the button with the up arrow button next to the document looking icon:
I guess the error you are getting in including PlotlyJS is because of this reason, my own PlutoUtils package should not have anything to do with it.
The error you got when trying to install my package is my fault, I removed the dependency to a package not in General now, but again you shouldn’t need my package to make the plot work, the only thing my package does with respect to plotting is directly creating the Base.show methods for PlotlyBase.Plot objects.