Task frequency dropdown initially missing arrow indicating it's a dropdown

See screen.
On initial creation, the dropdown for Task Frequency is missing the arrow indicating it's a dropdown. The repository arrow shows which may be a hint and shows just an issue with this field. The field works as it should (if you click into it it shows right values). Further, if you select a value, the arrow appears.
This is only an issue on initial creation. If you create one and go to create another, the arrow is there. If you edit first, then go to create, the arrow is there.
However the arrow vanishes again if you leave this page and go to another then return.

No errors in JS console including with ?debug on. No errors in nexus log.

I did not check older NX3 or NX2 at this time.
This may be recent regression (or something more subtle), as I do not recall encountering this when testing NEXUS-8528 (closed two days ago) and I created a lot of tasks for that.