I started a PhD on the boundaries between mathematics and biology.
I quit soon after finding out that my (mathematics) supervisor had been actively blocking me from communicating with biologists, including blocking meetings with my (biology) co-supervisor.
I gather they thought real, practical concerns would be a distraction from the purity of theoretical problems.
If it makes you feel any better these sort of games go on whenever cross discipline research occurs. It is all about controlling the research undertaken by the student.
I quit soon after finding out that my (mathematics) supervisor had been actively blocking me from communicating with biologists, including blocking meetings with my (biology) co-supervisor.
I gather they thought real, practical concerns would be a distraction from the purity of theoretical problems.