Headphones randomly play at full volume when switching between apps

I have an iPhone 15 on iOS 18.3.2.

In the last few days I’ve had an issue when connected to Bluetooth headphones where volume will randomly play at full volume. This is despite the headphone volume being low and the volume button not being touched. This normally happens when switching between apps or if a notification comes in. It can be solved by pressing the volume button down once, where the volume meter will reveal that the headphone volume is already set at its lowest and clicking it one lower will mute sound completely. Clicking it back up one will put it back into its normal volume, until it happens again.

This is still happening despite the headphone safety being limited to 75db.

It is happening with three different pairs of headphones I own, so I’m assuming it’s a software issue. As I’m sound sensitive I wear noise cancelling headphones most of the day and it’s really distressing when this happens and also my ears physically hurt and ring from how loud it is.

I doesn’t happen everytime I switch between apps but is more likely that the first sound I hear from an app after being opened will be at full volume. It seems to completely override the current volume settings without the phone volume meter changing.

Is anyone experiencing the same or have any suggestions? I haven’t changed any settings recently.