This happens to me with any application when maximizing. It also happens when using ctrl+super+up/down/left/right and when using ctrl+alt+num. It doesn't happen all the time though, sometimes the window is resized on the secondary monitor as expected, while other times its moved to the primary monitor. I haven't been able to detect any particular pattern for when the application is moved to the primary monitory and when it stays put.
This happens to me with any application when maximizing. It also happens when using ctrl+super+ up/down/ left/right and when using ctrl+alt+num. It doesn't happen all the time though, sometimes the window is resized on the secondary monitor as expected, while other times its moved to the primary monitor. I haven't been able to detect any particular pattern for when the application is moved to the primary monitory and when it stays put.