Obviously not all, but it sure feels like it. Going back 10ish years you have:
Lexie Brown-3rd Team All American as a sophomore, transfers out
Destiny Slocum-Big Ten Freshman of the Year, has a fantastic freshman year, transfers out.
Shakira Austin-All Big Ten 2nd Team as a sophomore, was becoming a really strong post presence for Maryland, transferred
Taylor Mikesell-2 year starter, Big Ten Freshman of the Year, still starting and playing at a high level as a sophomore, transfers out
Angel Reese-3rd Team All American as a sophomore, transfers out
Ashley Owusu-3rd Team All American as a sophomore, transfers out after injury riddled junior year
Others have transferred out and had brilliant careers elsewhere (Kiah Gillespie, Kiara Leslie, Jenna Staiti).
Aside from the UNC exodus in 2014/2015, I can't think of any other school that has had multiple high profile players transfer prior to graduation when they were a star player on a successful team. It's just bizarre that it only seems to happen at Maryland.
Worth noting, a lot of her standouts were not top 5/top 10 players coming out of high school (ex. Diamond Miller, Brionna Jones, Shatori Walker-Kimbrough, Kaila Charles, Shyanne Sellers) and her players often go on to become terrific pros.
Brenda clearly has an eye for talent and knows how to develop players, she just can't keep them.