This is the inaudible women problem. I have experienced it in meetings where my comment is met with silence and then some minutes later a male colleague makes the same comment and it is eagerly debated. I have had female friends experiencing exactly the same thing. And I have experienced it when trying to explain to a contractor what I want to have done to the gutters (he ignored me and I had to get a male neighbor to come and repeat what I said to get the right work done).

There was a study on this, many decades ago, where several meetings (maybe faculty meetings?) where recorded and then the various exchanges were analyzed. Women's comments tended to be ignored by both men and women.

So this is not new stuff and it is very real.

Not sure how to combat it though I do recall reading a few suggestions. You can join the conversation and say "given how Joe added to my initial suggestion, blah blah" but that might backfire, depending on how sexist others are. Or you can talk to a few people before meetings to create a group which agrees to discuss the proposals of each other and so give them more of an airing.