On this question, the accepted answer mentions key ghosting, although the actual issue the user is experiencing is key rollover.
This answer is not outright wrong and it has the potential of offering help to OP but it may just as easily mislead OP or anyone else looking to this question of guidance into buying a keyboard boasting "anti-ghosting" tech.
The result of an anti ghosting keyboard that does not have a higher key rollover would be that the key would be ignored just as in OP's experience.
What OP needs is a NKRO keyboard or either way a keyboard that is able to face the issue of key rollover AND ghosting.
Now to the question: Does this imprecision warrant an edit? Or a lengthy explanation in a new answer? Does it warrant a comment? or should this be left alone?
I did post a comment, not noticing this post was quite old already, mentioning this imprecision.
I believe this is different from general cases I've seen on the suggested answers like: What do we do with highly upvoted, accepted, wrong answers? as this is not technically a wrong answer but it has the potential to be misleading in it's imprecision.