Questioning Board and committees actions outside of a meeting

We have a 7 member board and one member wanted to vote on a unanimous action outside of a meeting to post a notice. The exact wording while important isn't shared here to not draw attention from the rest of my board members (I had talked to one of them in the past about online board communities), but here's most of it with the important phrases left in tact:

Does the board want to pursue posting a notice in regards to the restricted use HOA Common Property?

The board voted by email which our management company and board President say are legit (I'm still not so sure), but it has to be unanimous to pass. But there was a dissenting board member and led to a heated discussion and several emails to said board member to change his vote or at least abstain instead of saying no so they could get their notice posted. Effectively as the rest of the board reads it the board is to take no action on pursuing a notice.

I had actually voted for the notice in the first place but I am having issues the way that a few members of the board and President handled the issue after the initial vote. Unfortunately the original dissenting member has given up fighting on this issue and said he sent some motions about suspending the problem committee and voiding past decisions and something else to be forwarded by email but they will fail and he will just discuss it at our next meeting.

So what they did was go to the standing communications committee that consists of 3 board members that voted yes in the first place, came up with a new notice that notified of a city ordinance which still restricted the property use in the community in the exact same manner and the 3 members approved and posted the notice without notifying the board. The original dissenting board member and I were in contact after he saw the notice, he sent an email saying basically "who posted the notice that we didn't approve?" and the 2 of us removed all notices. Then the emails start about how 1 board member can't override the communications committee decision (a decision which we didn't even know about) and there were emails threatening to kick the dissenting voter off the board for improper conduct because he was appointed and not elected.

The way I see it they didn't like the outcome of the original vote so they moved it to a committee which consists of only board members supporting their notice. Is that even legal? Technically they are still board members "taking action to pursue a notice..." which failed to pass the whole board even though they CLAIM they were acting as the committee... I talked to a business lawyer I was discussing some other stuff with and he said it sounds "questionably legal at best" because they are both on the board and members of the committee and they are using the terms and roles very loosely.

Also the notices have been put back up by that committee member who originally posted them. Given that we have a divide on the board and we don't meet until after the notice in question no longer matters so this notice is a lost cause, but I'd like to know opinions on the questions I have about the events for future reference and action.

Here's the exact text of what the communications committee is allowed to do:
The Board of Directors of the HOA (the “Board”) shall establish a committee of the Board known as the Communications Committee (the “CC”). The CC shall consist of three (3) Board members. Members of the CC shall be chosen by the Board and shall review and approve all notices for posting on the message boards. Decisions by the CC shall be made by majority vote of the members of the CC.

The original issue was a question not a motion, is the default answer to the question with a dissenting board member no? or how does that work?
Given that the communications committee only approves and does not post notices, does the fact that the one lone board member posted these notices twice mean he just quickly switched hat to become a board member again when he went to post the notices?
Obviously members of the board were being shady acting like a communications committee to pass their agenda, but was the action legal?
We have other committees that could do these approvals should we use them instead of a subset of the board to avoid legal issues in the future?

Committees are advisory, so any "recommendations" that would come from a committee would have to be approved by the board for it to be official. (UNLESS your documents give this committee this power) No one committee member or board member should have posted this notice.

Some boards DO have the power to approve a motion over the phone or other electronical method IF it is unanimous, and then ratify it at the next meeting. The fact that you had a disenting voter means that it did not pass, and would have to presented at the next meeting (regular or called special for this purpose).