Yeah, this'll have nothing to do with Meridian. The head unit (Bosch/JLR) is what will be doing speed-related adjustments before sending the audio to the amplifier/DSP (LEAR). I do not believe the amplifier/DSP can be upgraded "over the air" and only in a dealership, so it's probably the head unit.

Our 2019 I-Pace had a bundle of problems after the December update (USB sticks stopped working, driver key detection for settings was broken, all logins forgotten) - but it fixed itself a few weeks later (either by another OTA update or other mystical process). The other possibility is that the December update was somehow lossy and the variant configuration (what peripherals are connected, what model it is) has somehow become corrupted.

If you don't mind losing your local data, you might find asking your dealership to perform the "NDU/New Dealer Update via Pathfinder" process (a rather magic phrase): it entirely reinstalls all the infotainment software fresh.

B.