Broker blocking direct deal-term discussions with seller — normal?

Curious to get some perspective here. I’m working on a deal for a business doing around $2M in revenue and $400K adjusted EBITDA. I’ve already had a Zoom call and an in-person site visit with the seller, GM, and office manager. The business seems strong overall, but the asking price is a bit rich — roughly 4x vs. 3x where I think it should land. The owner has engaged both a tax professional and an M&A attorney, and they’ve sent back some comments on the LOI. The edits aren’t terrible, but not great either. My main frustration is that the broker won’t allow me to discuss key deal terms directly with the seller — he insists that all negotiations go through him. I’ve asked a couple of times to have a joint call to align on major items, but he keeps blocking it. Is this typical behavior, or is it a red flag? Any advice on how to handle this without alienating the broker or the seller?