Ah! You must have one of the hardware platforms that I noted in my article that points to this forum post: Peplink | Pepwave - Forum
The super-old ethernet chipsets they were using caused issues that couldn’t be resolved without a switch in between. Not the best solution, but Peplink isn’t a huge vendor that Starlink really cares about, so getting them to change something was not going to happen. It also appeared to affect a number of other products out there using similar or identical ethernet chipsets.