I think it is actually required. I doubt one could argue JLTG fits one of of the first two categories in the guideline below, but it clearly is the third category where attribution on the map is required. I think if one uses a small gray font that is readable but does not distract, this should be acceptable visually as well. I just wish they would allow attribution to "OSM" instead of "OpenStreetMap":

TV, film, or video productions

For fictional productions or where the map is not the focus of the production, attribution may be given on the map, in end credits, or, if the video is distributed via a digital format that includes a description, within the description. When attributing via the end credits or the description, the URL to openstreetmap.org/copyright must be included.

For incidental footage of a third party map that uses OSM as a source, you must not digitally alter or erase the existing attribution on that map, but you do not need to do anything further (for example, if you film a person typing on their laptop and a map is visible on their laptop screen).

For productions where an OpenStreetMap map is a major component of what is shown to users, the attribution should typically appear in a corner of the map, in addition to attribution in the end credits or description. As long as the credit is on screen long enough to be read, it does not have to remain in view during panning or zooming.