OpenFit 2+: Background noise cancellation?

Hello! Fresh new Shokz user - have got the OpenFit 2+ recently.

Feedback from people I've had calls with has been mixed, and I'm interested to get to the bottom of this.

When walking on very busy streets, or even when cycling, I can have a phone conversation no problem. No complaints from the other side.

When I'm in an office setting, the mixed reviews start to flood in:

(1) If I'm talking, no issues - my speech is prioritised.

(2) When I'm not talking, the background noise is ramped up.

This is on Microsoft Teams; and I can confirm that the noise suppression function in Teams is On.

In the office setting, I'm connected to my laptop, whereas on the street / cycling, it's via my phone; and my phone has the Shokz app. I don't know if this makes a difference. Or to put it another way, I don't know where the noise cancellation processing is happening (and I am completely making up that phrase, in my attempt to try to understand the problem).

It feels like this is not a hardware issue, but a software issue; I just wanted to run the question by this group to see if it's Shokz-related at all.

Thanks all