I think that cursor is called Text Select, but I don't see any setting to change it.
I got this problem only on one machine for now. With Both Canary and Dev Builds 26080.1 and 26080.1100.
I don't know what the difference can be the cause for this issue.
Looks like the icon lost the transparency around the cursor and it is filled with black. 😎🤷♂️