How can we reproduce the issue?

You'd need to have access to IT Glue.

Does it work if you use an intermediate editor or text field to paste/copy this before pasting in Firefox as you do not seem to get plain text, so it is possible that Firefox gets confused by what flavors are present on the clipboard ?

I've spoken with Kaseya support who own IT Glue and they've confirmed this is an issue that they're aware of.

hello, I have this same issue. I found another site where this is an issue as well. When I try to share my bookings with me link it also copies [object promise] rather than the url

this is the outlook url where the image is taken from https://outlook.office.com/bookwithme/me

i did try an intermediate text editor as well and even in notepad all you get is [object promise]. in fact in the windows clipboard history (Win + V) it shows that [object promise] was copied to the clipboard. another image of that