Grammar may be correct while the question still sounds loaded.
“Why didn’t you consider the mobile app?”
This assumes the team failed to consider it.
Depending on your purpose:
“How does the current proposal affect the mobile app?”
“Was the mobile flow included in the estimate?”
“What would we need to change for mobile?”
The first question asks for impact, the second checks scope, and the third asks about work. Choose the question you actually mean.
This is also useful in written technical discussions. For review comments, see
how to disagree in a code review without sounding aggressive.