I am observing weird behavior in a webmap on 11.1 Portal when viewing the map in Edge.
I have a label class on a point feature layer using a custom expression: "✔". It is meant to look like this:

However, once labeling is enabled, the symbol for the point including the label disappears from the map.
The labels used to work fine last week. It also works fine in Chrome and in Edge on some virtual drives I have access to. Multiple users can replicate this error in Edge. We've had a companywide Windows update over the weekend which I suspect is the cause of this.
This is the error from Dev tools in Edge:

My theory is that the browser can't render the character for some reason due to a conflict with the fonts. I am not sure if the browser looks for the font locally or if it references a ESRI hosted font via network.
I am wondering If it is an internal issue, and I should mitigate with internal IT or if it is something on ESRI side of things.
I've tried replicating the symbol on an AGOL map and it renders the label fine using Edge. It comes up with the same error as above but it substitutes the font successfully.
@BjornSvensson I noticed you've responded to similar questions.