Exposed Audio Mixer group SEND Bug?

Hi,
There's something really weird going on here, or I'm doing something really stupid! :).

I created a Master group with 7 subgroups.
6 groups for audio
1 Reverb Receiver.

I applied a send to reverb group in each of the 6 groups.

When I expose the SEND LEVEL of Group1, all other SEND LEVELS of the other 5 groups become maked as exposed (with the arrow), but no exposed value appear on the EXPOSED PARAMETERS list, except of the one that I really applied (Send of Group1).

Am I doing someting wrong or is this a bug? I'm using Unity 2020.3.2f1.

PS: I've exposed other parameters like volume of the tracks without any problem. The problem appeared only when exposing the SEND LEVELS.

Thanks in advance!