Older Ipads Volume Sliders

Ive been having a bit of a strange issue with HA on my older wall mounted Ipads. Everything works as it should aside from volume sliders. I have Control4 and Heos integrations and for some reason a number of months ago the volume sliders just stopped working.

They are always stuck at 0. I can move my finger on them and change the volumes but the slider itself does not reflect this.

Are there any solutions to this at all?

Thank you