Bluetooth error during transmission (P20 Pro)?

Following problem:

I have a JBL Partybox 300. This can move the lights in time to the music with activated light show.

This also works so far with Iphone and OnePlus problem-free.

Unfortunately, this does not work so well with my Huawei P20 Pro. Here the light show starts only at a volume on the phone at 90%. Also, I do not regulate the box volume with the Handylautstärke. So I can make the box louder and I can make the phone louder. I set my phone to 100% and then regulate the volume exclusively on the box, then the light show is running, so the whole thing depends only on the phone.

If I connect an iPhone or a OnePlus, mobile phone and speaker volume are similar to each other. If I increase the volume on the phone, the volume of the box also increases directly.

Does anyone know why this is? Bluetooth versions, or differently adapted Android?

I hope I have explained everything understandable so far.

I often had the problem with my OnePlus 6 and the Bullets Wireless. For me it helped to disconnect the headphones from the device (decoupling) and then to pair again.

OnePlus has the option Maximum volume in Bluetooth mode. This synchronizes the volume between the speaker and smartphone. This feature could also be used on the P20 Pro under a similar name.

Thanks for the tip, I will try it out.

Apparently it is due to the option "media volume sync", which unfortunately does not exist under Huawei. Nevertheless, of course, thanks for the answer.