Drop-down arrow icon is missing in .ods

I have a .ods file in Nextcloud, and it opens perfectly. I don’t have any issues except for a small one, which is not a problem but it would be good to find the reason.
Some cells, when clicked, display an icon for the drop-down list they contain. This icon is an empty square, and the symbol of the drop-down list, which is the downward arrow, does not appear.
Locally edited with LibreOffice shows the drop-down arrow as expected.
Any idea?

Nextcloud Hub 7 (28.0.3) docker
Nextcloud Office 8.3.2
Collabora Online - Built-in CODE Server 23.5.904

*UPDATE i created a new ods file and have the same “issue”. Can anyone confirm or not?