In my experience, CEC is inconsistent. Sometimes the requests are fulfilled - sometimes they aren't. Sometimes you need to spam the requests, sometimes you need to switch the TV's input source to something else, Wii U or not, for it to work.
I'm not sure why this happens - possibly a timing issue? Maybe it only works at some specific memory alignment that happens at precise moments? But this should be investigated.
In my experience, CEC is inconsistent. Sometimes the requests are fulfilled - sometimes they aren't. Sometimes you need to spam the requests, sometimes you need to switch the TV's input source to something else, Wii U or not, for it to work.
I'm not sure why this happens - possibly a timing issue? Maybe it only works at some specific memory alignment that happens at precise moments? But this should be investigated.