I would like to share some findings regarding the Login Form redirect behavior in T4.
After updating the T4 System Plugin from 2.5.3 to 2.5.4, the issue reappeared:
the Login Form menu item always redirects to the user profile, and the “Menu Item Login Redirect” setting is ignored.
I noticed that in T4 System Plugin 2.5.4, the following file appears to have reverted to its previous state:
plugins/system/t4/themes/base/html/com_users/login/default_login.php
This file no longer generates a proper hidden "return" value for the login form, which causes Joomla to fall back to com_users/profile after login.
In my case, I worked around the issue by overriding the file in:
t4_bs5_blank/html/com_users/login/default_login.php
and adding an explicit hidden return field based on the Login Form menu parameters.
With this override in place, the Login Form redirect works as expected again.
However, since this issue seems to have been addressed before (at least partially) and then reintroduced in 2.5.4, it might be better to fix this at the framework level rather than requiring each site to add a manual override.
I wanted to share this in case it helps identify a regression or missing change in the T4 System Plugin.