Hello please let me know if this is the wrong place to post this thread.
I just had a heated argument with the owner/project manager of a music web app project we are working on. Being the UI/UX designer and one of two front-end developers in the team, I have sketched, drawn and did all the necessary things to design a user interface for both desktop and mobile. I following web design principles and practices that should be followed (5 months ago and was validated by the whole team)
The problem occurs today while following up on the developer's work so far, I realised that my fellow developer of the team altered the first part of the code that I sent to him and changed the UI as follows: - I designed the mobile website with a hamburger menu on the top left of the page and coded it as such, however the other developer added a bottom tab menu to the page containing 5 icons. (note that the whole website has exactly 7 categories in the menu)
Now as you can see we have now two menus on the page which I am concerned about. Once I point this out as a problem and something that should be avoided, the whole team doesn't agree with me and they are actually satisfied with with their solution. The project manager lets me know that that way .. we can have 5 categories on the bottom tab and the other two in the hamburger menu. Which to me doesn't make sense at all, seems wrong and a very very bad User experience. A feeling that I expressed of course but everyone seems to be against me and the project manager refused to let me show him evidence of why doing that is not good web design practice by literally letting me know that he is the boss and I do what he decides. Which of course I didn't take well because I'm not being paid for this (Oh by the way there is also a "Quick access" to 4 categories on the homepage, 4 categories that are also listed in the bottom menu.)
Here is my question guys. Please Am i wrong for thinking that this is bad design and bad User Experience? If No, how can I let them know they are heading in the wrong direction. If Yes, how come I haven't seen websites doing it yet and why does it seems like such a bad design practice.
Please help. Thank you and I apologise in advance if I posted this in the wrong place.