Hydrophone animation not working

[Compans57]

Just recently when I go to work the hydrophone, the needle doesn't visibly turn when I press Home/End, though the notepad to the left does cycle through bearings. Have I pressed one of the buttons on the pad or is this a known bug? It's not a deal breaker as I can still use it but it's nice to have a visual on the actual dial.

[Compans57]

Just for the record I finished the mission and started new patrol and it's working again.

I think the aerial got damaged in an attack.