What circumstances will cause "excel.application.ready" to become false?

I have recently stumbled into a weird bug where I am making a application.run call in an asynchronous handler. I encounter a crash with runtime error 50290 when I switch my worksheet from one to another. I am not editing any parts of the sheets but I am aware that these sheets have external link connection.

I have checked and confirmed that whenever the call fails it points to this variable application.ready being set to false during this worksheet switch.

I have no idea how this could happen